Nationwide mass vaccination highly effective against coronavirus disease 2019

1. A nationwide mass vaccination setting was shown to be effective against coronavirus disease 2019 (COVID-19) related outcomes such as infections, hospitalization, and death after the second dose.

2. The study did not include participants affiliated with medical roles or those exposed to a medical environment such as health care workers.

Evidence Rating Level: 2 (Good)

Study Rundown: With mass COVID-19 vaccination rollouts taking place, there is a need for a better understanding of the effects and benefits. As such, this study evaluated the effectiveness of the BNT162b2 vaccine in various subpopulations defined by age, gender, and co-existing conditions. The study determined patients that who received the second dose of the vaccine revealed better outcomes and greater effectiveness against COVID-19-related outcomes such as infections and hospitalization. This study was strengthened by its observational design and one-to-one matching of the control group and the variable group. However, the study results could not be applied to the general population because the study participants were composed of specific ethnic population groups. Similarly, the matching of study participants was limited due to vaccination rollout criteria such as older participants being vaccinated prior to younger participants. Finally, selection bias was another limiting factor in the study analysis. Nonetheless, the study results indicated strong evidence vaccine for the effectiveness against serious COVID-19 outcomes confirming the benefits of the BNT162b2 vaccine in a mass vaccination setting.

Click to read the study in NEJM

Relevant Reading: Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine

In-Depth [prospective cohort]: In this observational study, 1,193,236 participants have followed their first and second doses of the vaccine in Israel. This study enrolled patients aged 16 and older, with no previous history of COVID-19. Participants who received a vaccine between December 20^th, 2020, and February 1^st, 2021, were recruited into the study. Study participants with close contact within the health care system such as health care workers were all excluded from the study. The control group participants, the unvaccinated cohort, were matched one-to-one with participants in the vaccinated cohort based on age, gender, and ethnicity. The primary outcomes were a positive polymerase chain reaction (PCR) test for the infection, symptoms, hospital admission, disease severity, and death. The median age of both groups was 45 (interquartile range, 35 – 62). The study determined after 14 to 20 days, the first dose was 72% effective in preventing death (95% confidence interval [CI], 19 to 100), 46% in reducing documented infection (95% CI, 40 to 51), 57% for symptomatic COVID-19 infections (95% CI, 50 to 63), 74% in hospitalization rates (95% CI, 56 to 86), and 62% of disease severity (95% CI, 39 to 80). Additionally, after seven days after the second vaccination, 92% of the participants were protected against COVID-19 infections (95% CI, 88 to 95) and 87% of participants were protected against hospitalizations (95% CI, 55 to 100). Overall, the study revealed promising results in combating the COVID-19 infection-related outcomes in a mass vaccination setting.

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