FORdo and BioNTech’s Covid-19 vaccine performed as well in the real world as in the clinical trial that led to its use, concluded a large study in Israel.
The study, published on Wednesday in the New England Journal of Medicine, is the largest to date evaluating the vaccine’s effectiveness, comparing all illnesses, serious illnesses and hospitalizations, as well as deaths among 600,000 pairs of vaccinated and unvaccinated people.
The fact that a vaccine performs as well in the real world as it does in the highly controlled environment of a clinical trial is not taken for granted, noted senior author Ran Balicer, director of Israel’s Clalit Research Institute.
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“The vaccine fulfilled the promise that was there. And it was somewhat surprising to see that in a real-world environment, a vaccine was able to work as well as in the very controlled environment of a clinical trial, where the cold chain is perfect and people are being carefully selected, ”said Balicer , which also chairs a panel of experts advising the Israeli government on the pandemic.
But he cautioned that while the vaccine performed very well – it was 94% protective against symptomatic Covid, across all age groups, even in older adults – some fully vaccinated people developed serious illnesses and others died. During the study period, nine people who were fully vaccinated died from Covid-19, compared with 32 people who had not yet been vaccinated.
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“These vaccines are not a force field around you that denies you the chance of having a disease or of having a serious illness,” said Balicer, noting that while two doses of the vaccine offer substantial protection against severe Covid infection and death, “There is residual risk”.
“And so I think that continuing precautions, especially among those populations at risk … at a time when the spread of the community is evident and massive, as in the case of Israel, would be the most prudent thing to do, even for those who are fully vaccinated, “he said.
Kathleen Neuzil, director of the Vaccine Development Center at the University of Maryland School of Medicine, found the study’s results encouraging.
“This was a well done study and the results support the vaccine’s impact on several important results – any infection, symptomatic infection, hospitalizations and deaths,” she said. “The speed with which we are seeing the impact after the introduction of SARS-CoV-2 vaccines … gives hope that, with sufficient vaccine supply, we can control the pandemic.”
The study authors, from various institutions in Israel, as well as the Harvard School of Public Health and Boston Children’s Hospital, reported some data that will likely contribute to the ongoing debate about whether it would be safe to delay the second dose of the Pfizer vaccine. to give the first dose more quickly to more people.
The Pfizer vaccine is a two-dose vaccine that must be administered 21 days apart. Health officials in Britain have already decided to postpone the administration of the second dose, and some experts in the United States are pushing for the country to do the same. But so far, the Food and Drug Administration has resisted calls to change the virus’s dosing schedule.
Almost everyone in Israel who received the vaccine received their second dose at the right time, so the study cannot answer the question of how well the protection induced by the first dose of the vaccine would last if it were not reinforced at the appropriate time.
But the analysis showed that from the 14th day after the first injection – the point where the protection starts to take effect – until the 20th, the day before the second dose, there was moderate protection against any infection, but better protection against disease serious.
During that narrow window of time, protection against documented Covid infection after a dose was 46% – below the FDA limit of 50% efficacy. But for symptomatic infection, hospitalization and serious illness, the protection for this period was 57%, 74% and 62%, respectively.
The authors estimated that a dose of the vaccine was 72% protective against Covid’s death in that seven-day period, although due to the small number of deaths, it is difficult to draw firm conclusions.
The study also found that the vaccine worked well for people with significant health problems – another real-world test in which vaccines do not always pass with praise.
Noa Dagan, an author also at the Clalit Research Institute, said that for people with one or two health conditions that increase the risk of severe Covid disease, the vaccine worked just as well as for healthy people.
Even in people with three or more health problems, protection from the vaccine appeared to be strong, with about 89% effectiveness, she said.
As Covid vaccines begin to be used more widely, there will be a plethora of studies looking at how vaccines work and whether some work better in certain segments of the population than others. This data is sorely needed as the world tries to find the best way to use vaccines that will be scarce for months or more.
“I think the results are useful, as we can start leveraging large sets of observational data to fill in gaps in our understanding, especially by allowing more accurate analyzes by age, comorbidity and time since vaccination, as they did here,” said Natalie Dean, a biostatistics at the University of Florida.