Mary Wilson
Well-known member
A Retrospective Cohort Study
15 February 2022
https://doi.org/10.7326/M21-4130
Sivan Gazit, MD, MA, Roei Shlezinger, BA, Galit Perez, MN, MA, Roni Lotan, PhD, Asaf Peretz, MD, Amir Ben-Tov, MD, Esma Herzel, MSc, Hillel Alapi, BA, Dani Cohen, PhD, Khitam Muhsen, PhD, Gabriel Chodick, PhD, MHA, Tal Patalon, MD
Background:
There is insufficient evidence regarding the magnitude and durability of protection conferred by a combined effect of naturally acquired immunity after SARS-CoV-2 infection and vaccine-induced immunity.
Objective:
To compare the incidence rate of SARS-CoV-2 reinfection in previously infected persons to that of previously infected persons who subsequently received a single dose of BNT162b2 messenger RNA vaccine.
Design:
A retrospective cohort study emulating a randomized controlled target trial through a series of nested trials.
Setting:
Nationally centralized database of Maccabi Healthcare Services, Israel.
Participants:
Persons with documented SARS-CoV-2 infection who did not receive subsequent SARS-CoV-2 vaccination were compared with persons with documented SARS-CoV-2 infection who received a single dose of the BNT162b2 vaccine at least 3 months after infection.
Intervention:
Forty-one randomized controlled trials were emulated, in which 107 413 Maccabi Healthcare Services' members aged 16 years and older were eligible for at least 1 trial.
Measurements:
SARS-CoV-2–related outcomes of infection, symptomatic disease, hospitalization, and death, between 2 March and 13 December 2021.
Results:
A statistically significant decreased risk (hazard ratio, 0.18 [95% CI, 0.15 to 0.20]) for reinfection was found among persons who were previously infected and then vaccinated versus those who were previously infected but remained unvaccinated. In addition, there was a decreased risk for symptomatic disease (hazard ratio, 0.24 [CI, 0.20 to 0.29]) among previously infected and vaccinated persons compared with those who were not vaccinated after infection. No COVID-19–related mortality cases were found.
Limitation:
Hybrid protection against non-Delta variants could not be inferred.
Conclusion:
Persons previously infected with SARS-CoV-2 gained additional protection against reinfection and COVID-19 from a subsequent single dose of the BNT162b2 vaccine. Nonetheless, even without a subsequent vaccination, reinfection appeared relatively rare.
...
https://www.acpjournals.org/doi/10.7326/M21-4130#.YgraJ07pBXI.twitter
15 February 2022
https://doi.org/10.7326/M21-4130
Sivan Gazit, MD, MA, Roei Shlezinger, BA, Galit Perez, MN, MA, Roni Lotan, PhD, Asaf Peretz, MD, Amir Ben-Tov, MD, Esma Herzel, MSc, Hillel Alapi, BA, Dani Cohen, PhD, Khitam Muhsen, PhD, Gabriel Chodick, PhD, MHA, Tal Patalon, MD
Background:
There is insufficient evidence regarding the magnitude and durability of protection conferred by a combined effect of naturally acquired immunity after SARS-CoV-2 infection and vaccine-induced immunity.
Objective:
To compare the incidence rate of SARS-CoV-2 reinfection in previously infected persons to that of previously infected persons who subsequently received a single dose of BNT162b2 messenger RNA vaccine.
Design:
A retrospective cohort study emulating a randomized controlled target trial through a series of nested trials.
Setting:
Nationally centralized database of Maccabi Healthcare Services, Israel.
Participants:
Persons with documented SARS-CoV-2 infection who did not receive subsequent SARS-CoV-2 vaccination were compared with persons with documented SARS-CoV-2 infection who received a single dose of the BNT162b2 vaccine at least 3 months after infection.
Intervention:
Forty-one randomized controlled trials were emulated, in which 107 413 Maccabi Healthcare Services' members aged 16 years and older were eligible for at least 1 trial.
Measurements:
SARS-CoV-2–related outcomes of infection, symptomatic disease, hospitalization, and death, between 2 March and 13 December 2021.
Results:
A statistically significant decreased risk (hazard ratio, 0.18 [95% CI, 0.15 to 0.20]) for reinfection was found among persons who were previously infected and then vaccinated versus those who were previously infected but remained unvaccinated. In addition, there was a decreased risk for symptomatic disease (hazard ratio, 0.24 [CI, 0.20 to 0.29]) among previously infected and vaccinated persons compared with those who were not vaccinated after infection. No COVID-19–related mortality cases were found.
Limitation:
Hybrid protection against non-Delta variants could not be inferred.
Conclusion:
Persons previously infected with SARS-CoV-2 gained additional protection against reinfection and COVID-19 from a subsequent single dose of the BNT162b2 vaccine. Nonetheless, even without a subsequent vaccination, reinfection appeared relatively rare.
...
https://www.acpjournals.org/doi/10.7326/M21-4130#.YgraJ07pBXI.twitter
