Advances in COVID-19 mRNA vaccine development

In the paper

“Till now, all of these candidates have entered clinical trials (Table 5).130,376,377”

What the sources say

• Not checked yetcites [130] Sahin, U., Muik, A., Derhovanessian, E., Vogler, I. & Türeci, Z. Publisher Correction: COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses. Nature, 590, E17 (2021). source
• Not checked yetcites [376] Mulligan, M. J. et al. Phase 1/2 study to describe the safety and immunogenicity of a COVID-19 RNA Vaccine Candidate (BNT162b1) in adults 18 to 55 years of age: interim report. medRxiv, https://doi.org/10.1101/2020.06.30.20142570 (2020). source
• Not checked yetcites [377] Li, J. et al. Safety and immunogenicity of the SARS-CoV-2 BNT162b1 mRNA vaccine in younger and older Chinese adults: a randomized, placebo-controlled, double-blind phase 1 study. Nat. Med. 27, 1062–1070 (2021). source

In the paper

“Currently, five mRNA vaccines for influenza virus encoding the HA antigen have entered clinical trials: mRNA-1851, mRNA-1440, and mRNA-1010368,369 from Moderna; MRT-5400 and MRT-5401 co-developed by Sanofi and Translate Bio.370”

What the sources say

• Not checked yetcites [368] A seasonal flu investigational vaccine clinical trial for healthy adults, https://trials.modernatx.com/study/?id=mRNA-1010-P101 (2021).
• Not checked yetcites [369] Abbasi, J. Moderna’s mRNA vaccine for seasonal flu enters clinical trials. JAMA 326, 1365–1365 (2021).
• Not checked yetcites [370] Sanofi and Translate Bio Initiate Phase 1 Clinical Trial of mRNA Influenza Vaccine, https://translatebio.gcs-web.com/news-releases/news-release-details/sanofi-and-translate-bio-initiate-phase-1-clinical-trial-mrna (2021).

In the paper

“Several mRNA vaccine candidates for viral agents other than SARS-CoV-2 have entered clinical trials (Table 4), including CMV,359 influenza virus,288,360 rabies virus,86,88 Zika virus,90,361–364 RSV,365,366 human metapneumovirus (hMPV).367”

In the paper

“Non-replicating mRNA vaccines deliver exclusively genetic information coding for the target antigen, thus containing the 5′-cap, 5′ untranslated region (UTR), 3′ UTR, and 3′-poly(A) tail regions.108”

What the sources say

• Not checked yetcites [108] Pardi, N., Hogan, M. J., Porter, F. W. & Weissman, D. mRNA vaccines—a new era in vaccinology. Nat. Rev. Drug Discov. 17, 261–279 (2018). source

In the paper

“saRNA vaccines can deliver genetic information encoding the target antigen and other genes, e.g., viral RNA polymerase, to enable mRNA to self-replicate.109,110”

What the sources say

• Not checked yetcites [109] Blakney, A. K., Ip, S. & Geall, A. J. An update on self-amplifying mRNA vaccine development. Vaccines 9, 97 (2021). source
• Not checked yetcites [110] Atasheva, S. et al. Enhancement of protein expression by alphavirus replicons by designing self-replicating subgenomic RNAs. Proc. Natl Acad. Sci. USA 111, 10708–10713 (2014). source

In the paper

“Currently, COVID-19 mRNA vaccines BNT162b1 and BNT162b2 developed by BioNTech employ TriLink Cap1 cap analog (m27,3′-O)Gppp(m2′-O)ApG for co-transcriptional capping.27,130”

What the sources say

• Not checked yetcites [27] Vogel, A. et al. A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates. BioRxiv, https://doi.org/10.1101/2020.09.08.280818 (2020). source
• Not checked yetcites [130] Sahin, U., Muik, A., Derhovanessian, E., Vogler, I. & Türeci, Z. Publisher Correction: COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses. Nature, 590, E17 (2021). source

In the paper

“Since the 3′-OH group in proximity to m7G is methylated, thus the ARCA cap analog can only bind the 5′ end of mRNA in forward orientation, which is recognized by the eukaryotic translation initiation factor 4E (eIF4E) to initiate ribosome recruitment and translation.74,125”

What the sources say

• Not checked yetcites [74] Sahin, U., Karikó, K. & Türeci, Ö. mRNA-based therapeutics—developing a new class of drugs. Nat. Rev. Drug Discov. 13, 759–780 (2014). source
• Not checked yetcites [125] Grudzien-Nogalska, E. et al. Synthesis of anti-reverse cap analogs (ARCAs) and their applications in mRNA translation and stability. Methods Enzymol. 431, 203–227 (2007). source

In the paper

“A poly(A) tail of optimal length can improve translation efficiency and mRNA stability.150,151”

What the sources say

• Not checked yetcites [150] Tang, T. T. & Passmore, L. A. Recognition of poly (A) RNA through its intrinsic helical structure. Cold Spring Harb. Symp. Quant. Biol. 84, 21–30 (2019). source
• Not checked yetcites [151] Yu, S. & Kim, V. N. A tale of non-canonical tails: gene regulation by post-transcriptional RNA tailing. Nat. Rev. Mol. Cell Biol. 21, 542–556 (2020). source

In the paper

“Most COVID-19 mRNA vaccines currently in clinical trials or those already on the market are non-replicating mRNA vaccines.”

In the paper

“In contrast, the 5′ UTR is mostly retrieved from genes such as globin, Hsp70, axon dynein heavy chain 2 (DNAH2), and hydroxysteroid dehydrogenase (3β-HSD).144,145”

What the sources say

• Not checked yetcites [144] Carralot, J. P. et al. Polarization of immunity induced by direct injection of naked sequence-stabilized mRNA vaccines. Cell. Mol. Life Sci. 61, 2418–2424 (2004). source
• Not checked yetcites [145] Weng, Y. et al. The challenge and prospect of mRNA therapeutics lan-dscape. Biotechnol. Adv. 40, 107534 (2020). source

In the paper

“Design of proper 5′ and 3′ UTRs sequences is crucial for the success of mRNA vaccines.”

In the paper

“For instance, BioNTech uses a segmented poly(A) tail whose two-tail structures are connected in tandem by a 10 bp UGC linker sequence (A30LA70).27,153”

What the sources say

• Not checked yetcites [27] Vogel, A. et al. A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates. BioRxiv, https://doi.org/10.1101/2020.09.08.280818 (2020). source
• Not checked yetcites [153] Xia, X. Detailed dissection and critical evaluation of the Pfizer/BioNTech and Moderna mRNA vaccines. Vaccines 9, 734 (2021). source

In the paper

“In addition, circRNA has recently been developed for COVID-19 mRNA vaccines due to its natural high stability.112”

What the sources say

• Not checked yetcites [112] Qu, L. et al. Circular RNA vaccines against SARS-CoV-2 and emerging variants. BioRxiv, https://doi.org/10.1101/2021.03.16.435594 (2021). source

In the paper

“Many nucleoside-modified mRNA COVID-19 vaccines, including BNT162b2, BNT162b1, and BNT162b3 developed by BioNTech27,177; mRNA-1273, TAK919, mRNA-1273.211, mRNA-1273.351, mRNA-1283 developed by Moderna28,178; ChulaCov19 developed by Chulalongkorn University; and PTX-COVID19-B developed by Providence Therapeutics, have been approved for commercialization or entered clinical trials.104”

What the sources say

• Not checked yetcites [27] Vogel, A. et al. A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates. BioRxiv, https://doi.org/10.1101/2020.09.08.280818 (2020). source
• Not checked yetcites [177] Sahin, U. et al. COVID-19 vaccine BNT162b1 elicits human antibody and TH 1 T cell responses. Nature 586, 594–599 (2020). source
• Not checked yetcites [28] Corbett, K. S. et al. SARS-CoV-2 mRNA vaccine design enabled by prototype pathogen preparedness. Nature 586, 567–571 (2020). source
• Not checked yetcites [178] Corbett, K. S. et al. Immune Correlates of Protection by mRNA-1273 Immunization against SARS-CoV-2 Infection in Nonhuman Primates. BioRxiv, https://doi.org/10.1101/2021.04.20.440647 (2021). source
• Not checked yetcites [104] Chaudhary, N., Weissman, D. & Whitehead, K. A. mRNA vaccines for infectious diseases: principles, delivery and clinical translation. Nat. Rev. Drug Discov. 20, 817–838 (2021). source

In the paper

“The most advantageous aspect of saRNA vaccine is that it can be produced with ultra-low doses of saRNA.”

In the paper

“In contrast, Pardi and colleagues reported that protein levels after intradermal injection of m1ψ-modified mRNA in mice were 20 times higher compared to sequence-optimized but unmodified mRNA.184”

What the sources say

• Not checked yetcites [184] Pardi, N. et al. Nucleoside-modified mRNA vaccines induce potent T follicular helper and germinal center B cell responses. J. Exp. Med 215, 1571–1588 (2018). source

In the paper

“As a result, one copy of saRNA produces multiple copies of RNA transcripts by the above-described mechanism to initiate self-amplification of antigen genes in the cell.35,195,196”

What the sources say

• Not checked yetcites [35] Kim, J., Eygeris, Y., Gupta, M. & Sahay, G. Self-assembled mRNA vaccines. Adv. Drug Deliv. Rev. 170, 83–112 (2021). source
• Not checked yetcites [195] Pepini, T. et al. Induction of an IFN-mediated antiviral response by a self-amplifying RNA vaccine: implications for vaccine design. J. Immunol. 198, 4012–4024 (2017). source
• Not checked yetcites [196] Beal, J. et al. Model-driven engineering of gene expression from RNA replicons. ACS Synth. Biol. 4, 48–56 (2015). source

In the paper

“Hence, the delivery vector employed in saRNA vaccines must allow for higher loading capacity and encapsulation efficiency.35”

What the sources say

• Not checked yetcites [35] Kim, J., Eygeris, Y., Gupta, M. & Sahay, G. Self-assembled mRNA vaccines. Adv. Drug Deliv. Rev. 170, 83–112 (2021). source

In the paper

“In contrast, studies on mRNA vaccines with unmodified nucleosides have yielded inconsistent conclusions.”

In the paper

“The host immune system can easily recognize unmodified mRNA or by-products formed during IVT of engineered mRNA as exogenous molecules.74”

What the sources say

• Not checked yetcites [74] Sahin, U., Karikó, K. & Türeci, Ö. mRNA-based therapeutics—developing a new class of drugs. Nat. Rev. Drug Discov. 13, 759–780 (2014). source

In the paper

“taRNA technology has potential advantages in transfer capacity, versatility, and production scale-up, thus showing promising applications.217”

What the sources say

• Not checked yetcites [217] Fuller, D. H. & Berglund, P. Amplifying RNA vaccine development. N. Engl. J. Med 382, 2469–2471 (2020). source

In the paper

“Compared with the dose of mRNA in the Moderna vaccine (100 μg) and that of Pfizer-BioNTech vaccine (30 μg), the amount of saRNA required for vaccine development is within a range of 0.1~10 μg.212”

What the sources say

• Not checked yetcites [212] Pollock, K. M. et al. Safety and Immunogenicity of a Self-Amplifying RNA Vaccine Against COVID-19: COVAC1, a Phase I, Dose-Ranging Trial. EClinicalMedicine, https://doi.org/10.1016/j.eclinm.2021.101262 (2022). source

In the paper

“Engineered saRNA vaccines rely on the insertion of the gene encoding the target antigen into the genome of an RNA virus (mainly alphavirus) as well as the use of its replication machinery to amplify the delivered RNA, thereby increasing antigen expression.191–193”

What the sources say

• Not checked yetcites [191] Zhou, X., Berglund, P., Zhao, H., Liljeström, P. & Jondal, M. Generation of cytotoxic and humoral immune responses by nonreplicative recombinant Semliki Forest virus. Proc. Natl Acad. Sci. U.S.A. 92, 3009–3013 (1995). source
• Not checked yetcites [192] Smerdou, C. & Liljeström, P. Non-viral amplification systems for gene transfer: vectors based on alphaviruses. Curr. Opin. Mol. Ther. 1, 244–251 (1999).
• Not checked yetcites [193] Schott, J. W., Morgan, M., Galla, M. & Schambach, A. Viral and synthetic RNA vector technologies and applications. Mol. Ther. 24, 1513–1527 (2016). source

In the paper

“At present, taRNA technology has only been applied in preclinical studies for influenza vaccines.111”

What the sources say

• Not checked yetcites [111] Beissert, T. et al. A trans-amplifying RNA vaccine strategy for induction of potent protective immunity. Mol. Ther. 28, 119–128 (2020). source

In the paper

“In terms of structures, in addition to the conventional elements of non-replicating mRNA, saRNA contains a long ORF after 5′ UTR encoding the four NSPs (nsP1, nsP2, nsP3, and nsP4) of alphavirus that functions as an mRNA capping enzyme, an NTPase/helicase/protease, a macrodomain, or an RNA-dependent RNA polymerase (RDRP), respectively.”

What the sources say

• Not checked yetcites [194] Abu Bakar, F. & Ng, L. F. Nonstructural proteins of alphavirus—potential targets for drug development. Viruses 10, 71 (2018). source

In the paper

“taRNAs usually yield safer vaccines compared to saRNA vaccines.”

In the paper

“Thess and colleagues showed that unmodified, GC-rich mRNA engineered with an optimized UTR sequence yielded more sustained antigen expression compared to nucleoside-modified mRNA.183”

What the sources say

• Not checked yetcites [183] Thess, A. et al. Sequence-engineered mRNA without chemical nucleoside modifications enables an effective protein therapy in large animals. Mol. Ther. 23, 1456–1464 (2015). source

In the paper

“Furthermore, previous studies revealed significant differences in protein expression levels of target antigens when different signal peptides are selected.93”

What the sources say

• Not checked yetcites [93] Wollner, C. J. et al. A mRNA-LNP vaccine against Dengue Virus elicits robust, serotype-specific immunity. BioRxiv, https://doi.org/10.1101/2021.01.05.425517 (2021). source

In the paper

“Passage of mRNA through the phospholipid bilayer of the cell membrane is difficult due to its large molecular weight (104–106 Da), negative charge, and proneness to degradation by nucleases.”

In the paper

“Moreover, the vaccine also showed neutralizing activity against the Beta variant (B.1.351).”

What the sources say

• Not checked yetcites [112] Qu, L. et al. Circular RNA vaccines against SARS-CoV-2 and emerging variants. BioRxiv, https://doi.org/10.1101/2021.03.16.435594 (2021). source

In the paper

“To improve the safety, efficacy, and stability of mRNA vaccines, researchers usually performed codon optimization172,239–243 on the antigen-coding sequence to enhance translation efficiency.”

What the sources say

• Not checked yetcites [172] Mauger, D. M., Cabral, B. J., Presnyak, V., Su, S. V. & Mcfadyen, I. J. mRNA structure regulates protein expression through changes in functional half-life. Proc. Natl Acad. Sci. USA 116, 201908052 (2019). source
• Not checked yetcites [239] Hanson, G. & Coller, J. Codon optimality, bias and usage in translation and mRNA decay. Nat. Rev. Mol. Cell Biol. 19, 20–30 (2018). source
• Not checked yetcites [240] Presnyak, V. et al. Codon optimality is a major determinant of mRNA stability. Cell 160, 1111–1124 (2015). source
• Not checked yetcites [241] Buhr, F. et al. Synonymous codons direct cotranslational folding toward different protein conformations. Mol. Cell 61, 341–351 (2016). source
• Not checked yetcites [242] Yang, Y., Ma, X. & Huo, Y.-X. Application of codon optimization strategy in heterologous protein expression. Chin. J. Biotechnol. 35, 2227–2237 (2019).
• Not checked yetcites [243] Kudla, G., Murray, A. W., Tollervey, D. & Plotkin, J. B. Coding-sequence determinants of gene expression in Escherichia coli. Science 324, 255–258 (2009). source

In the paper

“Despite the lack of essential elements for cap-dependent translation, circRNA can be translated by adding the IRES element or m6A modification incorporated to its 5′ UTR region.223,224”

What the sources say

• Not checked yetcites [223] Wesselhoeft, R. A., Kowalski, P. S. & Anderson, D. G. Engineering circular RNA for potent and stable translation in eukaryotic cells. Nat. Commun. 9, 1–10 (2018). source
• Not checked yetcites [224] Yang, Y. et al. Extensive translation of circular RNAs driven by N 6-methyladenosine. Cell Res 27, 626–641 (2017). source

In the paper

“The trimeric S protein on the surface of SARS-CoV-2 plays a key role in mediating host cell invasion.”

What the sources say

• Not checked yetcites [228] Yao, H. et al. Molecular architecture of the SARS-CoV-2 virus. Cell 183, 730–738. e713 (2020). source
• Not checked yetcites [229] Lu, R. et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet 395, 565–574 (2020). source
• Not checked yetcites [230] Hsieh, C.-L. et al. Structure-based design of prefusion-stabilized SARS-CoV-2 spikes. Science 369, 1501–1505 (2020). source

In the paper

“The 2P mutation method is applicable to SARS-CoV-2271 and other β-coronavirus viruses,28”

What the sources say

• Not checked yetcites [271] Wrapp, D. et al. Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation. Science 367, 1260–1263 (2020). source
• Not checked yetcites [28] Corbett, K. S. et al. SARS-CoV-2 mRNA vaccine design enabled by prototype pathogen preparedness. Nature 586, 567–571 (2020). source

In the paper

“COVID-19 vaccines based on taRNA technology have not been reported.”

In the paper

“Liang and colleagues112 developed a circRNA vaccine against SARS-CoV-2 encoding a trimeric receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, considering that in RBD the signal peptide sequence of human tissue plasminogen activator (tPA) was fused to the N-terminus to ensure antigen secretion, whereas the trimerization motif of bacteriophage T4 fibritin protein (foldon) was fused to”

What the sources say

• Not checked yetcites [112] Qu, L. et al. Circular RNA vaccines against SARS-CoV-2 and emerging variants. BioRxiv, https://doi.org/10.1101/2021.03.16.435594 (2021). source

In the paper

“unmodified circRNA has been shown to induce TLR/RIG-I-mediated innate immune response compared to unmodified linear mRNA.225,226”

What the sources say

• Not checked yetcites [225] Wesselhoeft, R. A. et al. RNA circularization diminishes immunogenicity and can extend translation duration in vivo. Mol. Cell 74, 508–520. e504 (2019). source
• Not checked yetcites [226] Chen, Y. G. et al. Sensing self and foreign circular RNAs by intron identity. Mol. Cell 67, 228–238. e225 (2017). source

In the paper

“By adopting this strategy, two amino acids at the top of the helical position of the S2 subunit center are substituted with prolines (K986P and V987P), which was shown to improve stability of S protein in prefusion conformation effectively.”

In the paper

“Optimization of mRNA secondary structure244,245 and stability can be achieved by increasing the GC content of the coding sequence.246–248”

What the sources say

• Not checked yetcites [244] Zhong, C., Wei, P. & Zhang, Y. H. P. Enhancing functional expression of codon-optimized heterologous enzymes in Escherichia coli BL21(DE3) by selective introduction of synonymous rare codons. Biotechnol. Bioeng. 114, 1054–1064 (2016). source
• Not checked yetcites [245] Zhang, H. et al. Lineardesign: Efficient algorithms for optimized mrna sequence design. arXiv preprint arXiv:2004.10177, https://arxiv.org/abs/2004.10177 (2021).
• Not checked yetcites [246] Keiichi, H., Tamotsu, N. & Satoshi, F. Codon usage is less optimized in eukaryotic gene segments encoding intrinsically disordered regions than in those encoding structural domains. Nucleic Acids Res 44, 10051–10061 (2016).
• Not checked yetcites [247] Courel, M. et al. GC content shapes mRNA storage and decay in human cells. Elife 8, e49708 (2019). source
• Not checked yetcites [248] Kudla, G., Lipinski, L., Caffin, F., Helwak, A. & Zylicz, M. High guanine and cytosine content increases mRNA levels in mammalian cells. PLoS Biol. 4, e180 (2006). source

In the paper

“The covalently closed loop structure of circRNA protects from exonuclease degradation, thus increasing circRNA half-life and stability.”

In the paper

“previous studies have reported that cell transfection efficiency was maintained when circRNA was kept at room temperature for two weeks.112”

What the sources say

• Not checked yetcites [112] Qu, L. et al. Circular RNA vaccines against SARS-CoV-2 and emerging variants. BioRxiv, https://doi.org/10.1101/2021.03.16.435594 (2021). source

In the paper

“Moreover, since the S protein is trimeric, studies have shown that the trimeric motif of T4 bacteriophage fibritin introduced at the 3′ end of the coding region of the S protein or RBD protein can mimic the native structure of S protein and enhance antigen immunogenicity.141,277,278”

What the sources say

• Not checked yetcites [141] Zhang, B. Vaccines and compositions based on S antigen protein of SARS-CoV-2. CN112480217A (2021).
• Not checked yetcites [277] Walsh, E. E. et al. RNA-based COVID-19 vaccine BNT162b2 selected for a pivotal efficacy study. Medrxiv, https://doi.org/10.1101/2020.08.17.20176651 (2020). source
• Not checked yetcites [278] Walsh, E. E. et al. Safety and Immunogenicity of Two RNA-Based Covid-19 Vaccine Candidates. N. Engl. J. Med 383, 2439–2450 (2020). source

In the paper

“The S protein is cleaved into S1 and S2 subunits during viral infection by the Furin enzyme and transmembrane serine protease 2 (TMPRSS2).231,232”

What the sources say

• Not checked yetcites [231] Hoffmann, M., Kleine-Weber, H. & Pöhlmann, S. A multibasic cleavage site in the spike protein of SARS-CoV-2 is essential for infection of human lung cells. Mol. Cell 78, 779–784. e775 (2020). source
• Not checked yetcites [232] Hoffmann, M. et al. SARS-CoV-2 cell entry depends on ACE2 and TMPRSS2 and is blocked by a clinically proven protease inhibitor. Cell 181, 271–280. e278 (2020). source

In the paper

“In addition, vaccination with circRNA prepared with the original SARS-CoV-2 strain sequence followed by a booster dose of the vaccine containing circRNA prepared with Delta sequences conferred good protection against Delta and Omicron.”

What the sources say

• Not checked yetcites [227] Qu, L. et al. Circular RNA Vaccines against SARS-CoV-2 and Emerging Variants. BioRxiv, https://doi.org/10.1101/2021.03.16.435594 (2022). source

In the paper

“Therefore, the S protein is considered the main antigen for vaccine design.228–230”

What the sources say

• Not checked yetcites [228] Yao, H. et al. Molecular architecture of the SARS-CoV-2 virus. Cell 183, 730–738. e713 (2020). source
• Not checked yetcites [229] Lu, R. et al. Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet 395, 565–574 (2020). source
• Not checked yetcites [230] Hsieh, C.-L. et al. Structure-based design of prefusion-stabilized SARS-CoV-2 spikes. Science 369, 1501–1505 (2020). source

In the paper

“In addition, in vivo experiments in mice showed that the delivery efficiency of pABOL is higher than that of PEI carriers.”

What the sources say

• Not checked yetcites [323] Blakney, A. K. et al. Big is beautiful: enhanced saRNA delivery and immunogenicity by a higher molecular weight, bioreducible, cationic polymer. ACS Nano 14, 5711–5727 (2020). source

In the paper

“In addition to lipid and polymer carriers, peptides can also be used for mRNA delivery.331–333”

What the sources say

• Not checked yetcites [331] Li, W., Nicol, F. & Szoka, F. C. Jr GALA: a designed synthetic pH-responsive amphipathic peptide with applications in drug and gene delivery. Adv. Drug Deliv. Rev. 56, 967–985 (2004). source
• Not checked yetcites [332] McCarthy, H. O. et al. Development and characterization of self-assembling nanoparticles using a bio-inspired amphipathic peptide for gene delivery. J. Controlled Release 189, 141–149 (2014). source
• Not checked yetcites [333] Udhayakumar, V. K. et al. Arginine-rich peptide-based mRNA nanocomplexes efficiently instigate cytotoxic T cell immunity dependent on the amphipathic organization of the peptide. Adv. Healthc. Mater. 6, 1601412 (2017). source

In the paper

“Polymers are another widely used mRNA delivery system, and offer better physical stability than lipid carriers.”

In the paper

“In addition, protamine was shown to activate TLR7 and TLR8 pathways, thereby showing potential as a delivery vehicle with adjuvant effect for vaccines or gene therapy.188”

What the sources say

• Not checked yetcites [188] Kallen, K.-J. et al. A novel, disruptive vaccination technology: self-adjuvanted RNActive® vaccines. Hum. Vaccine Immunother. 9, 2263–2276 (2013). source

In the paper

“Finally, cationic squalene emulsions can be applicable for mRNA delivery.336,337”

What the sources say

• Not checked yetcites [336] Brito, L. A. et al. A cationic nanoemulsion for the delivery of next-generation RNA vaccines. Mol. Ther. 22, 2118–2129 (2014). source
• Not checked yetcites [337] Tsai, T. F. Fluad®-MF59®-adjuvanted influenza vaccine in older adults. Infect. Chemother. 45, 159–174 (2013). source

In the paper

“The findings of this study revealed that, compared with naked PbAE-mRNA, cellular transfection efficiency was greatly improved when LPP-coated PbAE-mRNA was used.”

What the sources say

• Not checked yetcites [326] Persano, S. et al. Lipopolyplex potentiates anti-tumor immunity of mRNA-based vaccination. Biomaterials 125, 81–89 (2017). source

In the paper

“The main role of PEGylated lipid in LNPs is to reduce aggregation and non-specific uptake by immune cells.304–306”

What the sources say

• Not checked yetcites [304] Hashizaki, K. et al. Effects of poly (ethylene glycol)(PEG) concentration on the permeability of PEG-grafted liposomes. Chem. Pharm. Bull. 53, 27–31 (2005). source
• Not checked yetcites [305] Hashizaki, K. et al. Effects of poly (ethylene glycol)(PEG) chain length of PEG-lipid on the permeability of liposomal bilayer membranes. Chem. Pharm. Bull. 51, 815–820 (2003). source
• Not checked yetcites [306] Kanasty, R., Dorkin, J. R., Vegas, A. & Anderson, D. Delivery materials for siRNA therapeutics. Nat. Mater. 12, 967–977 (2013). source

In the paper

“However, its delivery efficiency was 1,000 times lower than that of LNP employed in the Acuitas vaccine formulation.289,324”

What the sources say

• Not checked yetcites [289] Buschmann, M. D. et al. Nanomaterial delivery systems for mRNA vaccines. Vaccines 9, 65 (2021). source
• Not checked yetcites [324] Lipids and lipid nanoparticle formulations for delivery of nucleic acids. US10221127B2.

In the paper

“However, the vaccine was associated with increased risk of myocarditis in Israeli participants, reaching a rate of approximately 3 events per 100,000 persons.398–400”

What the sources say

• Not checked yetcites [398] Barda, N. et al. Safety of the BNT162b2 mRNA Covid-19 vaccine in a nationwide setting. N. Engl. J. Med. 385, 1078–1090 (2021). source
• Not checked yetcites [399] Mevorach, D. et al. Myocarditis after BNT162b2 mRNA vaccine against Covid-19 in Israel. N. Engl. J. Med. 385, 2140–2149 (2021). source
• Not checked yetcites [400] Witberg, G. et al. Myocarditis after Covid-19 vaccination in a large health care organization. N. Engl. J. Med. 385, 2132–2139 (2021). source

In the paper

“neutralization titers induced after two doses of BNT162b2 were 160, 7, 24, and 73 GMTs for wild-type SARS-CoV-2, Omicron, Beta, and Delta variants, respectively”

What the sources say

• Not checked yetcites [406] Muik, A. et al. Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine-elicited human sera. Science, 375, 678–680 (2022). source

In the paper

“However, results from clinical trials with over 5,000 people who had received BioNTech/Pfizer booster injections showed that protection conferred by the vaccine was 95.6%.392–394”

What the sources say

• Not checked yetcites [392] Pfizer. Pfizer and BioNTech announce Phase 3 trial data showing high efficacy of a booster dose of their COVID-19 vaccine, https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-phase-3-trial-data-showing (2021).
• Not checked yetcites [393] Bar-On, Y. M. et al. Protection of BNT162b2 vaccine booster against Covid-19 in Israel. N. Engl. J. Med. 385, 1393–1400 (2021). source
• Not checked yetcites [394] Romero-Ibarguengoitia, M. E. et al. Effect of the third dose of BNT162b2 vaccine in quantitative SARS-CoV-2 spike 1-2 IgG antibody titers in healthcare workers. medRxiv, https://doi.org/10.1101/2021.10.20.21265269 (2021). source

In the paper

“Clinical trial data indicated that both mRNA vaccine candidates induced neutralizing antibodies at a comparable level.”

What the sources say

• Not checked yetcites [277] Walsh, E. E. et al. RNA-based COVID-19 vaccine BNT162b2 selected for a pivotal efficacy study. Medrxiv, https://doi.org/10.1101/2020.08.17.20176651 (2020). source
• Not checked yetcites [278] Walsh, E. E. et al. Safety and Immunogenicity of Two RNA-Based Covid-19 Vaccine Candidates. N. Engl. J. Med 383, 2439–2450 (2020). source
• Not checked yetcites [378] Mulligan, M. J. et al. Phase I/II study of COVID-19 RNA vaccine BNT162b1 in adults. Nature 586, 589–593 (2020). source

In the paper

“The effectiveness of the BNT162b2 vaccine against the Beta variant was measured shortly after the population of Qatar had been vaccinated, whereas the effectiveness of BNT162b2 against the Delta variant was conducted several months after the second dose, which could be one of the reasons for low effectiveness of BNT162b2 against the Delta variant.404,405”

What the sources say

• Not checked yetcites [404] Abu-Raddad, L. J. et al. Pfizer-BioNTech mRNA BNT162b2 Covid-19 vaccine protection against variants of concern after one versus two doses. J. Travel Med. 28, taab083 (2021). source
• Not checked yetcites [405] Chemaitelly, H. & Abu-Raddad, L. J. Effectiveness of the BNT162b2 Covid-19 Vaccine against the B.1.1.7 and B.1.351 Variants. N. Engl. J. Med. 385, 187–189 (2021). source

In the paper

“As mentioned previously, protection conferred by BNT162b2 decreases significantly over time.”

In the paper

“However, the vaccine developers eventually decide to proceed with BNT162b2 to phase II/III international clinical trials in view of its milder reactogenicity.277,278,378”

What the sources say

• Not checked yetcites [277] Walsh, E. E. et al. RNA-based COVID-19 vaccine BNT162b2 selected for a pivotal efficacy study. Medrxiv, https://doi.org/10.1101/2020.08.17.20176651 (2020). source
• Not checked yetcites [278] Walsh, E. E. et al. Safety and Immunogenicity of Two RNA-Based Covid-19 Vaccine Candidates. N. Engl. J. Med 383, 2439–2450 (2020). source
• Not checked yetcites [378] Mulligan, M. J. et al. Phase I/II study of COVID-19 RNA vaccine BNT162b1 in adults. Nature 586, 589–593 (2020). source

In the paper

“BioNTech and Pfizer collaborated to develop five COVID-19 mRNA vaccine candidates at the beginning of the pandemic, which were based on nucleoside-modified mRNA (BNT162b2, BNT162b1, BNT162b3), non-modified mRNA (BNT162a1) and self-amplifying mRNA (BNT162c2).”

What the sources say

• Not checked yetcites [130] Sahin, U., Muik, A., Derhovanessian, E., Vogler, I. & Türeci, Z. Publisher Correction: COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses. Nature, 590, E17 (2021). source
• Not checked yetcites [376] Mulligan, M. J. et al. Phase 1/2 study to describe the safety and immunogenicity of a COVID-19 RNA Vaccine Candidate (BNT162b1) in adults 18 to 55 years of age: interim report. medRxiv, https://doi.org/10.1101/2020.06.30.20142570 (2020). source
• Not checked yetcites [377] Li, J. et al. Safety and immunogenicity of the SARS-CoV-2 BNT162b1 mRNA vaccine in younger and older Chinese adults: a randomized, placebo-controlled, double-blind phase 1 study. Nat. Med. 27, 1062–1070 (2021). source

In the paper

“The PEG additive,402 which is also used in several cosmetics and pharmaceutical drugs, has been incriminated as a possible cause for anaphylaxis induced by the BNT162b2 mRNA vaccine.”

What the sources say

• Not checked yetcites [402] Bruusgaard-Mouritsen, M. A., Johansen, J. D. & Garvey, L. H. Clinical manifestations and impact on daily life of allergy to polyethylene glycol (PEG) in ten patients. Clin. Exp. Allergy 51, 463–470 (2021). source

In the paper

“but improved to 368, 164, 279, and 413 GMTs, after one month following a booster vaccination.”

What the sources say

• Not checked yetcites [406] Muik, A. et al. Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine-elicited human sera. Science, 375, 678–680 (2022). source

In the paper

“In a mass vaccination study which included 3,159,136 participants from Israel, vaccine effectiveness of BNT162b2 as a two-dose scheme was 94%.397”

What the sources say

• Not checked yetcites [397] Dagan, N. et al. BNT162b2 mRNA Covid-19 vaccine in a nationwide mass vaccination setting. N. Engl. J. Med. 384, 1412–1423 (2021). source

In the paper

“Results of clinical trials have shown that mRNA-1273 is generally well tolerated and safe to use in adolescents and adults.”

What the sources say

• Not checked yetcites [410] Baden, L. R. et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N. Engl. J. Med. 384, 403–416 (2021). source
• Not checked yetcites [411] Moderna announces TeenCOVE study of its COVID-19 vaccine in adolescents meets primary endpoint and plans to submit data to regulators in early June, https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-teencove-study-its-covid-19-vaccine (2021).

In the paper

“with similar immune responses among adolescents aged 12 to 17.410,412–414”

What the sources say

• Not checked yetcites [410] Baden, L. R. et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N. Engl. J. Med. 384, 403–416 (2021). source
• Not checked yetcites [412] Ali, K. et al. Evaluation of mRNA-1273 SARS-CoV-2 vaccine in adolescents. N. Engl. J. Med. 385, 2241–2251 (2021). source
• Not checked yetcites [413] Teo, S. P. Review of COVID-19 mRNA Vaccines: BNT162b2 and mRNA-1273. J. Pharm. Pract., 08971900211009650, https://doi.org/10.1177/08971900211009650 (2021). source
• Not checked yetcites [414] Chu, L. et al. Immune memory response after a booster injection of mRNA-1273 for severe acute respiratory Syndrome Coronavirus-2 (SARS-CoV-2). medRxiv, https://doi.org/10.1101/2021.09.29.21264089 (2021). source

In the paper

“Comparable trends were observed in live virus neutralization testing.”

What the sources say

• Not checked yetcites [406] Muik, A. et al. Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine-elicited human sera. Science, 375, 678–680 (2022). source

In the paper

“The low performance of CVnCoV in phase II clinical trials has been attributed to the rise of multiple SARS-CoV-2 variants.”

What the sources say

• Not checked yetcites [425] Kremsner, P. G. et al. Efficacy and safety of the CVnCoV SARS-CoV-2 mRNA vaccine candidate in ten countries in Europe and Latin America (HERALD): a randomised, observer-blinded, placebo-controlled, phase 2b/3 trial. Lancet Infect. Dis., https://doi.org/10.1016/s1473-3099(21)00677-0 (2021). source

In the paper

“PTX-COVID19-B was shown to induce high titers of neutralizing antibodies against wild-type SARS-CoV-2 and variants, including Alpha, Beta, and Delta, which were comparable to those elicited by the approved COVID-19 mRNA vaccines when assessed by the same neutralization assay.431,432”

What the sources say

• Not checked yetcites [431] Abe, K. T. et al. Neutralizing antibody responses to SARS-CoV-2 variants in vaccinated Ontario long-term care home residents and workers. medRxiv, https://doi.org/10.1101/2021.08.06.21261721 (2021). source
• Not checked yetcites [432] Providence Therapeutics Reports PTX-COVID19-B, its mRNA Vaccine for COVID-19, Neutralizes SARS-CoV-2 and Variants of Concern, Including Delta, https://providencetherapeutics.com/article-details/providence-therapeutics-reports-ptx-covid19-b-its-mrna-vaccine-for-covid-19-neutralizes-sars-cov-2-and-variants-of-concern-including-delta.html (2021).

In the paper

“Other studies have shown that mRNA-1273 is still quite effective in congregate settings or higher-risk exposure such as prisons or hospitals in which the Delta variant was prevalent.419,420”

What the sources say

• Not checked yetcites [419] Chin, E. T. et al. Effectiveness of the mRNA-1273 vaccine during a SARS-CoV-2 Delta outbreak in a prison. N. Engl. J. Med., https://doi.org/10.1056/NEJMc2114089 (2021). source
• Not checked yetcites [420] Paris, C. et al. Effectiveness of mRNA-BNT162b2, mRNA-1273, and ChAdOx1 nCoV-19 vaccines against COVID-19 in healthcare workers: an observational study using surveillance data. Clin. Microbiol. Infect. (2021). source

In the paper

“Mid-term results of phase I clinical trial of MRT5500 showed that the seroconversion rate was 91% to 100%.”

What the sources say

• Not checked yetcites [436] Sanofi to focus its COVID-19 development efforts on the recombinant vaccine candidate, https://www.sanofi.com/en/media-room/press-releases/2021/2021-09-28-18-44-47-2304800 (2021).
• Not checked yetcites [437] Sanofi announces positive Phase 1/2 study interim results for its first mRNA-based vaccine candidate, https://www.sanofi.com/en/media-room/press-releases/2021/2021-09-28-08-00-00-2304069 (2021).

In the paper

“The low vaccination dosage of CVnCoV and the use of unmodified nucleotides might have contributed to the performance of this vaccine in phase II clinical trials compared to the licensed COVID-19 vaccine.428”

What the sources say

• Not checked yetcites [428] Cohen, J. What went wrong with CureVac’s mRNA vaccine? Science 372, 1381 (2021). source

In the paper

“Among the three booster vaccines evaluated, the multivalent mRNA-1273.211 induced the largest geometric mean titers (GMT) for variants Beta, Gamma and Delta.415,416”

What the sources say

• Not checked yetcites [415] Choi, A. et al. Safety and immunogenicity of SARS-CoV-2 variant mRNA vaccine boosters in healthy adults: an interim analysis. Nat. Med., https://doi.org/10.1038/s41591-021-01527-y (2021). source
• Not checked yetcites [416] Wu, K. et al. Preliminary analysis of safety and immunogenicity of a SARS-CoV-2 variant vaccine booster. Medrxiv, https://doi.org/10.1101/2021.05.05.21256716 (2021). source

In the paper

“However, none of the vaccinated individuals with three doses of mRNA-1273 were hospitalized, which indicates a promising alternative.421”

What the sources say

• Not checked yetcites [421] Tseng, H. F. et al. Effectiveness of mRNA-1273 against SARS-CoV-2 omicron and delta variants. medRxiv, 2022.2001.2007.22268919, https://doi.org/10.1101/2022.01.07.22268919 (2022). source

In the paper

“Similar findings suggest that vaccination with three doses of the mRNA vaccine BNT162b2 may protect against Omicron-mediated COVID-19.407,408”

What the sources say

• Not checked yetcites [407] Liu, L. et al. Striking antibody evasion manifested by the Omicron variant of SARS-CoV-2. Nature, https://doi.org/10.1038/s41586-021-04388-0 (2021). source
• Not checked yetcites [408] Planas, D. et al. Considerable escape of SARS-CoV-2 Omicron to antibody neutralization. Nature, https://doi.org/10.1038/s41586-021-04389-z (2021). source

In the paper

“In a phase III clinical trial involving 30,420 people, participants aged 18 or older were given two doses of 100 μg of mRNA-1273 with a 28-day interval, and vaccine efficacy was 94.1% (Table 5)”

What the sources say

• Not checked yetcites [410] Baden, L. R. et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N. Engl. J. Med. 384, 403–416 (2021). source
• Not checked yetcites [412] Ali, K. et al. Evaluation of mRNA-1273 SARS-CoV-2 vaccine in adolescents. N. Engl. J. Med. 385, 2241–2251 (2021). source
• Not checked yetcites [413] Teo, S. P. Review of COVID-19 mRNA Vaccines: BNT162b2 and mRNA-1273. J. Pharm. Pract., 08971900211009650, https://doi.org/10.1177/08971900211009650 (2021). source
• Not checked yetcites [414] Chu, L. et al. Immune memory response after a booster injection of mRNA-1273 for severe acute respiratory Syndrome Coronavirus-2 (SARS-CoV-2). medRxiv, https://doi.org/10.1101/2021.09.29.21264089 (2021). source

In the paper

“Thus vaccine booster with BNT162b2 may enhance neutralization of the Omicron variant.406”

What the sources say

• Not checked yetcites [406] Muik, A. et al. Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine-elicited human sera. Science, 375, 678–680 (2022). source

In the paper

“However, current results of clinical trials suggest that immunogenicity profiles of saRNA vaccines may not be comparable to those obtained with non-self-replicating mRNA vaccines.”

In the paper

“This might likely reflect differences in exogenous RNA restriction by the innate immune sensing.”

In the paper

“In addition, ultra-low temperature preservation is more conducive to maintaining the original conformation of mRNA-LNP complexes.468”

What the sources say

• Not checked yetcites [468] Mamontov, E., Daemen, L. L., Novak, E. & Stone, M. B. Melting and re-freezing leads to irreversible changes in the morphology and molecular-level dynamics of Pfizer-BioNTech COVID-19 Vaccine. Medicina 57, https://doi.org/10.3390/medicina57121343 (2021). source

In the paper

“The management of LNPs encapsulation is directly related to the quality of the final mRNA vaccine, particularly involving target gene sequence design, raw materials, mRNA purity and integrity, and mRNA/lipid ratio.”

In the paper

“Previous studies showed that the protein yield of mRNA purified by reverse phase HPLC increases by 10–1000 times.156,453”

What the sources say

• Not checked yetcites [156] Kariko, K., Muramatsu, H., Ludwig, J. & Weissman, D. Generating the optimal mRNA for therapy: HPLC purification eliminates immune activation and improves translation of nucleoside-modified, protein-encoding mRNA. Nucleic Acids Res 39, e142–e142 (2011). source
• Not checked yetcites [453] Ssr, A., Dmfp, A., Ama, A. & Mpcm, B. mRNA vaccines manufacturing: Challenges and bottlenecks. Vaccine 39, 2190–2200 (2021). source

In the paper

“Quality control of COVID-19 mRNA vaccines focuses on raw materials (plasmids, biobanks, lipids, nucleotides, and enzymes used in the production process), semi-finished, and final product.445,465”

What the sources say

• Not checked yetcites [445] Center for Drug Evaluation. Guideline on the Chemistry, Manufacture and Control (CMC) of Prophylactic COVID-19 mRNA Vaccines (trial), https://www.nmpa.gov.cn/directory/web/nmpa/images/2020081423091712896.docx (2020).
• Not checked yetcites [465] Poveda, C., Biter, A. B., Bottazzi, M. E. & Strych, U. Establishing preferred product characterization for the evaluation of RNA vaccine antigens. Vaccines 7, 131 (2019). source

In the paper

“Therefore, existing COVID-19 mRNA vaccines undoubtedly require storage under ultra-low temperatures.469”

What the sources say

• Not checked yetcites [469] Uddin, M. N. & Roni, M. A. Challenges of storage and stability of mRNA-Based COVID-19 vaccines. Vaccines 9, https://doi.org/10.3390/vaccines9091033 (2021). source

In the paper

“In fact, mRNA vaccines that have been licensed for clinical trials, commercialization, or emergency use must currently be stored and delivered at low temperatures.”

In the paper

“saRNA vaccines have dosage advantages compared to the approved mRNA vaccines BNT162b2, mRNA-1273, and other non-replicating mRNA vaccines.”

In the paper

“Thus, incorporation of encoded modulators of human PRR or of a wider range of potential modifications may positively affect immunogenicity and efficacy of saRNA vaccines.443,444”

What the sources say

• Not checked yetcites [443] Hagai, T. et al. Gene expression variability across cells and species shapes innate immunity. Nature 563, 197–202 (2018). source
• Not checked yetcites [444] Blakney, A. K. et al. Innate inhibiting proteins enhance expression and immunogenicity of self-amplifying RNA. Mol. Ther. 29, 1174–1185 (2021). source

In the paper

“The mRNA vaccine should be stored and transported under ultra-low temperature conditions, due to the intrinsic instability of mRNA.”

In the paper

“Although the mRNA vaccine is a new technology and its production relatively simple for scaling-up, most approaches employed during the process are sophisticated, thus quality control of mRNA vaccine production still represents a challenge.454”

What the sources say

• Not checked yetcites [454] Center for Drug Evaluation. Guiding principles for research and development technical of COVID-19 preventive vaccines (trial), https://www.nmpa.gov.cn/zhuanti/yqyjzxd/yqyjxd/20200814230916157.html (2020).