Viral loads of Delta-variant SARS-CoV2 breakthrough infections following vaccination and booster with the BNT162b2 vaccine
Open accessPreprint — published as 10.1038/s41591-021-01575-4 · Paper page
Abstract
The BNT162b2 vaccine showed high real-life effectiveness both at preventing disease and in reducing viral loads of breakthrough infections, but coincidental with the rise of the Delta-variant SARS-CoV2, these protective effects have been decreasing, prompting a third, booster, vaccine inoculation. Here, analyzing viral loads of over 11,000 infections during the current wave in Israel, we find that even though this wave is dominated by the Delta-variant, breakthrough infections in recently vaccinated patients, still within 2 months post their second vaccine inoculation, do have lower viral loads compared to unvaccinated patients, with the extent of viral load reduction similar to pre-Delta breakthrough observations. Yet, this infectiousness protection starts diminishing for patients two months post vaccination and ultimately vanishes for patients 6 months or longer post vaccination. Encouragingly, we find that this diminishing vaccine effectiveness on breakthrough infection viral loads is restored following the booster vaccine. These results suggest that the vaccine is initially effective in reducing infectiousness of breakthrough infections even with the Delta variant, and that while this protectiveness effect declines with time it can be restored, at least temporarily, with a booster vaccine.
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The period after fourth dose vaccination in Israel has been dominated by the omicron variant, which makes assessing the relative effectiveness of the fourth dose against other covid-19 variants difficult.
“A second limitation stems from the varying dominance of different SARS-CoV-2 variants over time. The period after fourth dose vaccination in Israel has been dominated by the omicron variant, which makes assessing the relative effectiveness of the fourth dose against other covid-19 variants difficult—a well recognised limitation of real world analyses during this pandemic.6 36 37”
The protective effect of BNT162b2 against SARS-CoV-2 infection peaks after the second dose and then quickly declines, with the humoral immune response sharply decreasing.
“Studies have shown that the protective effect of BNT162b2 against SARS-CoV-2 infection peaks after the second dose and then quickly declines, with the humoral immune response sharply decreasing.388–391”
From Advances in COVID-19 mRNA vaccine development (2022) · cites this paper as [391]
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Cites
Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine
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MethodSix Month Safety and Efficacy of the BNT162b2 mRNA COVID-19 Vaccine
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Transmission dynamics and epidemiological characteristics of Delta variant infections in ChinaPreprint
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Advances in COVID-19 mRNA vaccine development
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Self-citation
- Authors
- Levine-Tiefenbrun, M., Yelin, I., Alapi, H., Katz, R., Herzel, E., Kuint, J., Chodick, G., Gazit, S., Patalon, T., & Kishony, R.
- Affiliations
- Tel Aviv University (IL)
- Technion – Israel Institute of Technology (IL)
- Maccabi Healthcare Services (IL)
- Corresponding author
- Patalon, Tal
- Kishony, Roy
- ORCID
- Venue
- Nature Medicine
- Publisher
- openRxiv
- Published
- 2021-09-01
- Volume
- 27
- Issue
- 12
- Pages
- 2108-2110
- ISSN
- 1078-8956 (ISSN-L)
- OpenAlex
- W3209028723
- Cited by
- 222
- References
- 9
- Citations by year
- 2026: 5 · 2025: 11 · 2024: 20 · 2023: 39 · 2022: 132 · 2021: 15
- FWCI
- 16.30
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Nature Medicine (publishedVersion)
- medRxiv (acceptedVersion, cc-by-nc)
- PubMed (publishedVersion)
- Funders
- Israel Science Foundation (3633/19)
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Health Sciences › Medicine › Infectious Diseases › COVID-19 Clinical Research Studies
- Keywords
- SARS-CoV-2, Delta variant, breakthrough infection, viral load, BNT162b2, COVID-19 vaccines, booster vaccination, waning vaccine effectiveness, infectiousness, time since vaccination, Israel
- MeSH terms
- COVID-19, SARS-CoV-2, COVID-19 Vaccines, BNT162 Vaccine, Breakthrough Infections, Antibodies, Viral, Humans, Immunization, Secondary, Israel, Time Factors, Vaccination, Viral Load, Antibodies, Neutralizing
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