Pfizer-BioNTech COVID-19 Vaccine Significantly Prevents Infection, Severe Disease in Israel
New real-world research suggest the vaccine may help provide control of the pandemic virus.
Two-dose administration of Pfizer-BioNTech COVID-19 vaccine BNT162b2 is associated with greater than 90% prevention of asymptomatic, symptomatic and severe COVID-19 infection, according to new real-world findings out of Israel.
The three-month study outcomes from the nation with the greatest rate of vaccinated adults showed persons aged ≥16 years old given the two-dose mRNA vaccine have similarly benefitted in substantial risk reduction from hospitalization (97.5%) and death (96.7%) related to the pandemic virus.
Investigators, led by Dr. Sharon Alroy-Preis, of the Israel Ministry of Health published in The Lancet Wednesday evening, believe these newest real-world outcomes provide evidence of future control over COVID-19 among a more vaccinated global population.
“Until this point, no country in the world had described the national public health impact of a nationwide COVID-19 vaccination campaign,” Alroy-Preis said in a statement. “These insights are hugely important because, while there are still some considerable challenges to overcome, they offer real hope that COVID-19 vaccination will eventually enable us to control the pandemic.”
The new study was borne out of Israel’s Ministry of Health campaign to immunize the approximate 6.5 million residents aged ≥16 years old following the emergency authorization of BNT162b2 for such eligible individuals.
Alroy-Preis and colleagues conducted a real-world efficacy estimation study of two-dose vaccine against SARS-CoV-2 infection and outcomes, with added consideration to nationwide public health impact of the vaccine’s introduction to the Israel population.
Their study used national surveillance data from January 24 – April 3 of this year to define the total cases of laboratory-confirmed SARS-CoV-2 infections and disease-related outcomes, including asymptomatic and symptomatic infection, COVID-19 hospitalization, severe or critical hospitalization, and death.
Vaccine efficacy against such outcomes were calculated by comparison of their occurrence in fully-vaccinated persons (≥7 days after their second dose) versus non-vaccinated persons.
Decade-length age groups, sex, and calendar weeks were used to adjust the binomial regression model for vaccine efficacy assessment.
Additionally, the investigators estimated the prevalence of the then-spreading B.1.1.7 variant in Israel through the proportion of spike gene target failures on PCR tests among the nationwide sample of SARS-CoV-2 positive specimens.
In total, the team observed 232,268 SARS-CoV-2 infections, 7694 COVID-19 hospitalizations, 4481 severe or critical hospitalizations, and 1113 COVID-19 deaths among people aged ≥16 in the observed time period.
Israel’s eligible population was 72.1% fully vaccinated with 2 doses of BNT162b2 by April 3.
Vaccine effectiveness at ≥7 days following the second dose, adjusted for demographics, were as follows for the selected outcomes:
- 95.3% against SARS-CoV-2 infection (95% CI, 94.9 – 95.7)
- 91.5% against asymptomatic SARS-CoV-2 infection (95% CI, 90.7 – 92.2)
- 97.0% against symptomatic COVID-19 (95% CI, 96.7 – 97.2)
- 97.2% against COVID-19 related hospitalization (95% CI, 96.8 – 97.5)
- 97.5% against severe or critical hospitalization (95% CI, 97.1 – 97.8)
- 96.7% against COVID-19 related death (95% CI, 96.0 – 97.3)
Investigators additionally observed that across all age groups, SARS-CoV-2 outcome incidence declined with increasing vaccine coverage—meaning a more vaccinated population was associated with decreased SARS-CoV-2 infection and COVID-19 illness and death.
The B.1.1.7 variant, understood to be more transmissible than the most prevalent strain of SARS-CoV-2, was prevalent in 94.5% of all observed infection samples from that time period.
Alroy-Preis and colleagues concluded the two-dose BNT162b2 COVID-19 vaccine is “highly effective” across all groups in preventing all observed virus outcomes, included those causes by the B.1.1.7 variant.
“Finally, the high effectiveness against all SARS-CoV-2 infections and apparent effectiveness against infections that were asymptomatic at the time of epidemiological investigation suggest that BNT162b2 might reduce SARS-CoV-2 transmission,” investigators wrote. “Taken together, these findings suggest that high vaccine uptake can meaningfully stem the pandemic and offers hope for eventual control of the SARS-CoV-2 outbreak as vaccination programmes ramp up across the rest of the world.”