SARS-CoV-2 reinfection in a cohort of 43,000 antibody-positive individuals followed for up to 35 weeks
Open accessPreprint — published as 10.1016/j.eclinm.2021.100861
Abstract
Background: Reinfection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented, raising public health concerns. Risk and incidence rate of SARS-CoV-2 reinfection were assessed in a large cohort of antibody-positive persons in Qatar. Methods: All SARS-CoV-2 antibody-positive persons with a PCR-positive swab ≥14 days after the first-positive antibody test were individually investigated for evidence of reinfection. Viral genome sequencing was conducted for paired viral specimens to confirm reinfection. Incidence of reinfection was compared to incidence of infection in the complement cohort of those antibody-negative. Results: Among 43,044 anti-SARS-CoV-2 positive persons who were followed for a median of 16.3 weeks (range: 0-34.6), 314 individuals (0.7%) had at least one PCR positive swab ≥14 days after the first-positive antibody test. Of these individuals, 129 (41.1%) had supporting epidemiological evidence for reinfection. Reinfection was next investigated using viral genome sequencing. Applying the viral-genome-sequencing confirmation rate, the risk of reinfection was estimated at 0.10% (95% CI: 0.08-0.11%). The incidence rate of reinfection was estimated at 0.66 per 10,000 person-weeks (95% CI: 0.56-0.78). Incidence rate of reinfection versus month of follow-up did not show any evidence of waning of immunity for over seven months of follow-up. Meanwhile, in the complement cohort of 149,923 antibody-negative persons followed for a median of 17.0 weeks (range: 0-45.6), risk of infection was estimated at 2.15% (95% CI: 2.08-2.22%) and incidence rate of infection was estimated at 13.69 per 10,000 person-weeks (95% CI: 13.22-14.14). Efficacy of natural infection against reinfection was estimated at 95.2% (95% CI: 94.1-96.0%). Reinfections were less severe than primary infections. Only one reinfection was severe, two were moderate, and none were critical or fatal. Most reinfections (66.7%) were diagnosed incidentally through random or routine testing, or through contact tracing. Conclusions: Reinfection is rare. Natural infection appears to elicit strong protection against reinfection with an efficacy ∼95% for at least seven months.
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In Qatar, a retrospective study of more than 43,000 participants estimated a 95% reduction of infection in seropositive individuals over a median of 114 days from a seropositive test.
“A retrospective study of more than 43,000 participants in a national database in Qatar has estimated a reduction of infection of 95% in seropositive individuals over a median of 114 days from a seropositive test (preprint data, not yet peer reviewed)54.”
From Prospects for durable immune control of SARS-CoV-2 and prevention of reinfection (2021) · cites this paper as [54]
Natural SARS-CoV-2 infection has been estimated to give 89-95% protection, a level statistically indistinguishable from that of licensed vaccines in the short term.
“a level of protection that is not significantly different to the 89–95% protection that has been estimated following natural infection53,54.”
From Prospects for durable immune control of SARS-CoV-2 and prevention of reinfection (2021) · cites this paper as [54]
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- Authors
- Abu-Raddad, L. J., Chemaitelly, H., Coyle, P., Malek, J. A., Ahmed, A. A., Mohamoud, Y. A., Younuskunju, S., Ayoub, H. H., Kanaani, Z. A., Kuwari, E. A., Butt, A. A., Jeremijenko, A., Kaleeckal, A. H., Latif, A. N., Shaik, R. M., Rahim, H. F. A., Nasrallah, G. K., Yassine, H. M., Al Kuwari, M. G., Romaihi, H. E. A., Al-Thani, M. H., Khal, A. A., & Bertollini, R.
- Affiliations
- Cornell University (US)
- Hamad Medical Corporation (QA)
- Qatar University (QA)
- Ministry of Public Health (QA)
- Corresponding author
- Abu-Raddad, Laith J.
- ORCID
- Abu-Raddad, Laith J.
- Chemaitelly, Hiam
- Coyle, Peter
- Malek, Joel A.
- Mohamoud, Yasmin A.
- Younuskunju, Shameem
- Ayoub, Houssein H.
- Kanaani, Zaina Al
- Kuwari, Einas Al
- Butt, Adeel A.
- Jeremijenko, Andrew
- Kaleeckal, Anvar Hassan
- Latif, Ali Nizar
- Shaik, Riyazuddin Mohammad
- Rahim, Hanan F. Abdul
- Nasrallah, Gheyath K.
- Yassine, Hadi M.
- Al Kuwari, Mohamed G.
- Romaihi, Hamad Eid Al
- Al-Thani, Mohamed H.
- Bertollini, Roberto
- Venue
- EClinicalMedicine
- Publisher
- openRxiv
- Published
- 2021-01-15
- Volume
- 35
- Pages
- 100861-100861
- ISSN
- 2589-5370 (ISSN-L)
- PMC
- PMC8079668
- OpenAlex
- W3158562059
- Cited by
- 201
- References
- 1
- Citations by year
- 2026: 3 · 2025: 6 · 2024: 10 · 2023: 29 · 2022: 81 · 2021: 72
- FWCI
- 15.19
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- cc-by
- Locations
- EClinicalMedicine (publishedVersion, cc-by)
- medRxiv (acceptedVersion)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- LSHTM Research Online (London School of Hygiene and Tropical Medicine) (acceptedVersion, public-domain)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Qatar University QSpace (Qatar University) (submittedVersion, cc-by)
- Qatar University QSpace (Qatar University) (submittedVersion)
- Funders
- Hamad Medical Corporation
- Ministry of Public Health
- Weill Cornell Medical College
- Weill Cornell Medicine - Qatar
- 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 reinfection, COVID-19 pandemic, SARS-CoV-2 antibodies, natural immunity, antibody waning, viral genome sequencing, Qatar, contact tracing, incidence rate estimation, young adults, international travelers
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