The Israeli study shows the real effectiveness of Pfizer-BioNTech’s COVID-19 vaccine
Researchers conducted an analysis of nationwide surveillance data from Israel showing the real effectiveness of Pfizer-BioNTech’s BNT162b2 vaccine in protecting against infections with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) – the causative agent of 2019 coronavirus disease ( COVID-19).
The team – from Israel’s Ministry of Health in Jerusalem, Pfizer in Collegeville, Philadelphia, and Pfizer Pharmaceuticals Israel in Herzliya – reports that a significant and sustained decrease in the incidence of SARS-CoV-2 infections has been observed, including in older adults People vaccinated with two doses of the vaccine began to rise.
Sharon Alroy-Preis and colleagues say the results demonstrate the positive public health effects of a nationwide vaccination campaign and hope that vaccination against SARS-CoV-2 will ultimately control the pandemic.
In The Lancet, the researchers write, “These results are of international concern as vaccination programs increase in the rest of the world, suggesting that other countries may similarly see significant and sustained decreases in SARS-CoV-2 incidence if they achieve a high vaccine intake value. “
Israel launched a campaign to vaccinate 6.5 million people
The Pfizer-BioNTech BNT162b2 vaccine was approved for emergency use in Israel in December 2020 after its high effectiveness in protecting against symptomatic COVID-19 was demonstrated in a randomized controlled trial in people aged 16 and over.
Following approval for emergency use, the Israeli Ministry of Health launched a nationwide campaign to give two doses of the vaccine (21 days apart) to the 6 ∙ 5 million residents of Israel aged 16 and over (71% of the population).
By April 3, 2021, 61% of the population had received at least one dose of the vaccine.
Alroy-Price and colleagues say preliminary estimates of the effectiveness of a BNT162b2 dose have been reported from Denmark, Israel, the UK, and the US, and estimates have been described for two doses for a subset of the Israeli population participating in a health maintenance organization.
“However, estimates of the effectiveness of two doses of BNT162b2 against a range of SARS-CoV-2 results, including in older adults, have not been published,” they add. “Additionally, population estimates of the impact of a COVID-19 vaccine on the incidence of SARS-CoV-2 infection have not been reported.”
What did the researchers do?
Alroy-Preis and colleagues estimated the actual effectiveness of two doses of BNT162b2 against a series of SARS-CoV-2 results using national surveillance data from the first four months (January 24 to April 3, 2021) of the vaccination campaign.
They compared the incidence rates of SARS-CoV-2 infections (asymptomatic and symptomatic), COVID-19-related hospitalizations, major or critical hospitalizations, and death from the disease in fully vaccinated individuals (who had been 7 days in a second) Dose) with the rates in non-vaccinated individuals.
The researchers also used the percentage of spike gene target failures (SGTF) in polymerase chain reaction (PCR) tests among a nationwide convenience sample of SARS-CoV-2 positive samples to determine the prevalence of B.1.1 .7 variant to estimate.
“The SARS-CoV-2 variant B.1.1.7, which was first identified in the UK and is associated with increased transferability, has surfaced in several countries and was first reported in Israel on December 23, 2020,” says the team .
What did you find?
By April 3, 4,714,932 (72 ∙ 1%) of 6,538,911 people aged 16 and over had been completely immunized with two doses of BNT162b2.
During the study period, there were 232,268 SARS-CoV-2 infections, 7,694 COVID-19 hospitalizations, 4,481 cases of severe or critical hospitalizations and 1,113 deaths due to the disease.
After adjustment for age, gender and calendar week, the effectiveness of a full BNT162b2 vaccination was 95–3% against an overall SARS-CoV-2 infection; 91 ∙ 5% against asymptomatic infections, 97 ∙ 0% against symptomatic COVID-19, 97 ∙ 2% against hospital stays, 97 ∙ 5% against severe or critical hospital stays and 96 ∙ 7% against death from the disease.
The estimates of vaccine effectiveness against all SARS-CoV-2 results were over 96% in people age 75 and older.
Across all age groups, the 7-day moving average of SARS-CoV-2 infection cases decreased significantly with increasing cumulative vaccine coverage, the team reports.
“Steeper and earlier declines were observed, particularly in older age groups with higher and earlier vaccine coverage,” said Alroy-Preis and colleagues.
The variant B.1.1.7 was the dominant strain
During the analysis period, 94.5% of the 8,472 samples tested showed SGTF, which proves that BNT162b2 is effective against variant B.1.1.7.
“This study showed that two doses of BNT162b2, including in older adults, were highly effective against laboratory-confirmed SARS-CoV-2 infections and COVID-19 hospitalizations, major illness and death in a nationwide observational study of variant B.1.1. 7 was the dominant variety, ”say the researchers.
The high efficacy observed was confirmed by a significant decrease in the incidence of SARS-CoV-2 infections with increasing vaccine coverage, the team adds.
What did the authors conclude from this?
“These data provide nationwide evidence of the positive public health effects of a COVID-19 vaccination campaign,” write Alroy-Preis and colleagues.
“Taken together, these results suggest that high vaccine intake can significantly contain the pandemic and offer hope for possible control of the SARS-CoV-2 outbreak if vaccination programs increase in the rest of the world,” they conclude.