tetano
Editor, Senior Moderator
N Engl J Med
. 2022 Feb 16.
doi: 10.1056/NEJMoa2118691. Online ahead of print.
Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection
Victoria Hall[SUP] 1 [/SUP], Sarah Foulkes[SUP] 1 [/SUP], Ferdinando Insalata[SUP] 1 [/SUP], Peter Kirwan[SUP] 1 [/SUP], Ayoub Saei[SUP] 1 [/SUP], Ana Atti[SUP] 1 [/SUP], Edgar Wellington[SUP] 1 [/SUP], Jameel Khawam[SUP] 1 [/SUP], Katie Munro[SUP] 1 [/SUP], Michelle Cole[SUP] 1 [/SUP], Caio Tranquillini[SUP] 1 [/SUP], Andrew Taylor-Kerr[SUP] 1 [/SUP], Nipunadi Hettiarachchi[SUP] 1 [/SUP], Davina Calbraith[SUP] 1 [/SUP], Noshin Sajedi[SUP] 1 [/SUP], Iain Milligan[SUP] 1 [/SUP], Yrene Themistocleous[SUP] 1 [/SUP], Diane Corrigan[SUP] 1 [/SUP], Lisa Cromey[SUP] 1 [/SUP], Lesley Price[SUP] 1 [/SUP], Sally Stewart[SUP] 1 [/SUP], Elen de Lacy[SUP] 1 [/SUP], Chris Norman[SUP] 1 [/SUP], Ezra Linley[SUP] 1 [/SUP], Ashley D Otter[SUP] 1 [/SUP], Amanda Semper[SUP] 1 [/SUP], Jacqueline Hewson[SUP] 1 [/SUP], Silvia D'Arcangelo[SUP] 1 [/SUP], Meera Chand[SUP] 1 [/SUP], Colin S Brown[SUP] 1 [/SUP], Tim Brooks[SUP] 1 [/SUP], Jasmin Islam[SUP] 1 [/SUP], Andre Charlett[SUP] 1 [/SUP], Susan Hopkins[SUP] 1 [/SUP], SIREN Study Group
Affiliations
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.).
. 2022 Feb 16.
doi: 10.1056/NEJMoa2118691. Online ahead of print.
Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection
Victoria Hall[SUP] 1 [/SUP], Sarah Foulkes[SUP] 1 [/SUP], Ferdinando Insalata[SUP] 1 [/SUP], Peter Kirwan[SUP] 1 [/SUP], Ayoub Saei[SUP] 1 [/SUP], Ana Atti[SUP] 1 [/SUP], Edgar Wellington[SUP] 1 [/SUP], Jameel Khawam[SUP] 1 [/SUP], Katie Munro[SUP] 1 [/SUP], Michelle Cole[SUP] 1 [/SUP], Caio Tranquillini[SUP] 1 [/SUP], Andrew Taylor-Kerr[SUP] 1 [/SUP], Nipunadi Hettiarachchi[SUP] 1 [/SUP], Davina Calbraith[SUP] 1 [/SUP], Noshin Sajedi[SUP] 1 [/SUP], Iain Milligan[SUP] 1 [/SUP], Yrene Themistocleous[SUP] 1 [/SUP], Diane Corrigan[SUP] 1 [/SUP], Lisa Cromey[SUP] 1 [/SUP], Lesley Price[SUP] 1 [/SUP], Sally Stewart[SUP] 1 [/SUP], Elen de Lacy[SUP] 1 [/SUP], Chris Norman[SUP] 1 [/SUP], Ezra Linley[SUP] 1 [/SUP], Ashley D Otter[SUP] 1 [/SUP], Amanda Semper[SUP] 1 [/SUP], Jacqueline Hewson[SUP] 1 [/SUP], Silvia D'Arcangelo[SUP] 1 [/SUP], Meera Chand[SUP] 1 [/SUP], Colin S Brown[SUP] 1 [/SUP], Tim Brooks[SUP] 1 [/SUP], Jasmin Islam[SUP] 1 [/SUP], Andre Charlett[SUP] 1 [/SUP], Susan Hopkins[SUP] 1 [/SUP], SIREN Study Group
Affiliations
- PMID: 35172051
- DOI: 10.1056/NEJMoa2118691
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.).