Country-wide COVID-19 vaccine study finds Pfizer provides 95% protection

The first nation-wide COVID-19 vaccine effectiveness study has been published in The Lancet. Tracking nearly 5 million people fully vaccinated in Israel, the study found vaccination provides more than 95 percent protection from infection, hospitalization, severe illness, and death.

As Israel faced a major surge of COVID-19 infections in December it began one of the biggest and fastest country-wide vaccination campaigns in the world. Almost exclusively deploying the Pfizer mRNA COVID-19 vaccine the country had fully vaccinated over 70 percent of its adult population by early April.

"As the country with the highest proportion of its population vaccinated against COVID-19, Israel provides a unique real-world opportunity to determine the effectiveness of the vaccine and to observe wider effects of the vaccination programme on public health,” says Sharon Alroy-Preis, lead author on the new study from the Israel Ministry of Health.

The study reports a striking 95.3 percent protection from symptomatic SARS-CoV-2 infection seven days after a second vaccine dose. Protection against asymptomatic infection in fully vaccinated individuals was 91.5 percent.

The study also examined vaccine effectiveness after one dose finding 57.7 percent protection from infection 7 to 14 days after an initial Pfizer dose. This indicates one dose of this vaccine offers some protection but affirms previous data indicating two doses are crucial in generating effective immunity from disease.

“These data confirm the Pfizer mRNA vaccine provides very high protection from serious COVID19 disease and death – even in older more vulnerable people,” says Jonathan Ball, from the University of Nottingham. “Importantly, the study shows that two doses of the vaccine significantly increase levels of immunity and protection. This is why it is important that people get both doses.”

In late January Israel’s current wave peaked at more than 10,000 new cases a day. Three months later the country reported just 28 new cases on the May 8.

It is important to note Israel did not achieve this dramatic fall in cases through vaccination alone. The country was subject to major restrictions from late December, and a lockdown that lasted until early March.

However, the researchers do note the data indicates high vaccine coverage in certain age groups effectively corresponded with case reductions, pointing to vaccinations as the primary driver of this drop in SARS-CoV-2 infections.

“… even after reopenings occurred, SARS-CoV-2 incidence remained low, suggesting that high vaccine coverage might provide a sustainable path towards resuming normal activity,” the study concludes.

The study also notes the B.1.1.7 variant, commonly referred to as the UK variant, was most prevalent in the country across this period of time. This indicates the vaccine is effective against this variant, although the prominence of other variants was low so it is unclear whether these strong numbers hold up against other iterations of the virus.

"Until this point, no country in the world had described the national public health impact of a nationwide COVID-19 vaccination campaign,” says Alroy-Preis. “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 published in The Lancet.

Source: The Lancet