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Eric Topol: Prior Covid (“Natural Immunity”)
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Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection
List of authors.
- Victoria Hall, F.F.P.H.,
- Sarah Foulkes, M.Sc.,
- Ferdinando Insalata, M.Sc.,
- Peter Kirwan, B.Sc.,
- Ayoub Saei, Ph.D.,
- Ana Atti, M.Sc.,
- Edgar Wellington, M.Sc.,
- Jameel Khawam, M.Sc.,
- Katie Munro, M.Sc.,
- Michelle Cole, D.B.M.S.,
- Caio Tranquillini, M.D.,
- Andrew Taylor-Kerr, M.P.P.,
- Nipunadi Hettiarachchi, B.Sc.,
- Davina Calbraith, Ph.D.,
- Noshin Sajedi, M.Sc.,
- Iain Milligan, M.R.C.P.,
- Yrene Themistocleous, M.B., Ch.B.,
- Diane Corrigan, F.F.P.H.,
- Lisa Cromey, M.F.P.H.,
- Lesley Price, Ph.D.,
- Sally Stewart, M.Sc.,
- Elen de Lacy, M.Sc.,
- Chris Norman, M.Sc.,
- Ezra Linley, Ph.D.,
- Ashley D. Otter, Ph.D.,
- Amanda Semper, D.Phil.,
- Jacqueline Hewson, Ph.D.,
- Silvia D’Arcangelo, Ph.D.,
- Meera Chand, F.R.C.Path.,
- Colin S. Brown, F.R.C.Path.,
- Tim Brooks, F.R.C.Path.,
- Jasmin Islam, Ph.D.,
- Andre Charlett, Ph.D.,
- and Susan Hopkins, F.R.C.P.
for the SIREN Study Group*
Abstract
Background
The duration and effectiveness of immunity from infection with and vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are relevant to pandemic policy interventions, including the timing of vaccine boosters.
Methods
We investigated the duration and effectiveness of immunity in a prospective cohort of asymptomatic health care workers in the United Kingdom who underwent routine polymerase-chain-reaction (PCR) testing. Vaccine effectiveness (≤10 months after the first dose of vaccine) and infection-acquired immunity were assessed by comparing the time to PCR-confirmed infection in vaccinated persons with that in unvaccinated persons, stratified according to previous infection status. We used a Cox regression model with adjustment for previous SARS-CoV-2 infection status, vaccine type and dosing interval, demographic characteristics, and workplace exposure to SARS-CoV-2.
Results
Of 35,768 participants, 27% (9488) had a previous SARS-CoV-2 infection. Vaccine coverage was high: 97% of the participants had received two doses (78% had received BNT162b2 vaccine [Pfizer–BioNTech] with a long interval between doses, 9% BNT162b2 vaccine with a short interval between doses, and 8% ChAdOx1 nCoV-19 vaccine [AstraZeneca]). Between December 7, 2020, and September 21, 2021, a total of 2747 primary infections and 210 reinfections were observed. Among previously uninfected participants who received long-interval BNT162b2 vaccine, adjusted vaccine effectiveness decreased from 85% (95% confidence interval [CI], 72 to 92) 14 to 73 days after the second dose to 51% (95% CI, 22 to 69) at a median of 201 days (interquartile range, 197 to 205) after the second dose; this effectiveness did not differ significantly between the long-interval and short-interval BNT162b2 vaccine recipients. At 14 to 73 days after the second dose, adjusted vaccine effectiveness among ChAdOx1 nCoV-19 vaccine recipients was 58% (95% CI, 23 to 77) — considerably lower than that among BNT162b2 vaccine recipients. Infection-acquired immunity waned after 1 year in unvaccinated participants but remained consistently higher than 90% in those who were subsequently vaccinated, even in persons infected more than 18 months previously.
Conclusions
Two doses of BNT162b2 vaccine were associated with high short-term protection against SARS-CoV-2 infection; this protection waned considerably after 6 months. Infection-acquired immunity boosted with vaccination remained high more than 1 year after infection. (Funded by the U.K. Health Security Agency and others; ISRCTN Registry number, ISRCTN11041050. opens in new tab.)
For the whole report:
https://www.nejm.org/doi/full/10.1056/NEJMoa2118691
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