Israeli data suggest possible reduced efficacy of Pfizer vaccine

While Israel is suffering from a new surge in coronavirus cases, the Ministry of Health said on Thursday that the Pfizer-BioNTech vaccine remains highly effective against severe illness, but its protection against coronavirus infections is this. He reported that it may have dropped significantly compared to winter and early spring.

Analyzing the government’s national health statistics, researchers found that Pfizer Shot was only 39% effective in preventing infections in late June and early July, compared to 95% in January-early April. I estimated. However, in both periods, shots were more than 90% effective in preventing severe illness.

Israeli scientists warned that the new study was much smaller than the first study and measured cases in a narrower time frame. As a result, a much wider range of uncertainty is adjacent to their estimates, which can also be distorted by a variety of other factors.

Dr. Ran Balicer, chair of Israel’s Covid-19 National Expert Advisory Committee, said the challenge of accurately estimating vaccine efficacy was “immeasurable.” He said that a more careful analysis of the raw data is needed to understand what is happening.

Eran Segal, a biologist at the Weizmann Institute of Science, a vaccine consultant for the Israeli government, said:

Nonetheless, new estimates raise concerns that vaccines may lose some of their effectiveness in both Israel and elsewhere, including the United States. Possible reasons include the rise of the highly contagious Delta variant and the loss of protection from shots over time.

Israel launched an aggressive campaign with the Pfizer vaccine in January, with 58% of the population fully vaccinated, achieving one of the highest vaccination rates in the world. At the start of the campaign, government researchers began to estimate how much Shot shot reduced the risk for people getting Covid-19.

they Release May results based on records from January 24th to April 3rd. They estimated that the vaccine was 95% effective in preventing infection by the domestic coronavirus. In other words, the risk of getting Covid-19 was reduced by almost 100% in vaccinated people compared to unvaccinated people. Researchers also estimated that the vaccine was 97.5 percent effective against severe illness.

From a peak of more than 8,600 cases a day in January, the number of cases plummeted in the months that followed, with only dozens of cases being positive every day across Israel. Vaccines are most likely involved in the reduction, along with the strict government restrictions imposed on travel and conferences.

Israel began to relax regulations in the spring. In late June, the number of incidents surged again. Currently, more than 1000 people are positive every day, and Israel is recovering some restrictions this week.

Some of the people tested positive for the coronavirus in the new surge were completely vaccinated. Epidemiologists expected such a breakthrough infectious disease, Like all vaccines.

Researchers at the Ministry of Health have reviewed the effectiveness of the vaccine and limited the analysis to a surge from June 6th to July 3rd.During that period, the effectiveness of the vaccine in infection prevention 64 percent..

Recently, they performed another analysis. This time, they examined cases from June 20th to July 17th. During that period, they estimated that the vaccine was even less effective, only 39 percent against infection.

Nevertheless, they estimated that the effectiveness of the vaccine against serious illness remained high at 91.4 percent.

A vaccine efficacy of 39% does not mean that 61% of vaccinated people are infected with the coronavirus. Instead, it means that vaccinated people have a 39% lower risk of infection compared to unvaccinated people. Therefore, even at that low rate, the data show that vaccinated people are at significantly less risk of getting infected than unvaccinated people.

A small number of up-to-date studies means that the true effectiveness may be low or high. What makes the numbers even more uncertain is the fact that the new surge has not yet spread evenly across the country. Travelers with highly contagious delta mutants brought it back to areas with relatively high vaccination rates.

The new outbreak has not yet overwhelmed the low-vaccination orthodox Jewish and Arab-Israeli communities. The imbalance can make the vaccine less effective than it really is.

Also, the ages of vaccinated people vary significantly during the various periods studied. For example, a person who was vaccinated in January is very different from a person who was vaccinated in April. I was over 60 years old. If more people are vaccinated in January, they may not need to be infected. The vaccine itself, but there are other factors that are older or that researchers have not yet considered.

Still, the new estimates prompted some researchers to think about what’s happening with the vaccine. Delta variants became more common in Israel in June and may be better at avoiding vaccines.

In the UK, where Delta began to surge earlier this year, researchers estimated the efficacy of the Pfizer-BioNTech vaccine against variants based on reviews from all UK vaccinated by 16 May. .. report The New England Journal of Medicine states that it is 88% effective against symptomatic Covid-19.

Another possibility is that the Pfizer-BioNTech vaccine is becoming less effective. Researchers at the Ministry of Health have found that people vaccinated in January have a higher proportion of breakthrough infections than those vaccinated in April.

If the vaccine actually declines after 6 months, the effects are immeasurable. It could affect the Israeli government’s current deliberations on whether to give people a third shot.Dr. Seagull says it may be wise to deploy the vaccine if it actually loses some of its potency. booster To fight the delta-led outbreak.

“If the third booster is safe and it seems to really benefit, I think this should definitely be done as soon as possible,” he said.

Dr. Barriser, who is also Chief Innovation Officer at Clarit Health Services, said he and his colleagues used Clarit’s medical records to take into account such confounding factors and are unique about the effectiveness of vaccines in Israel. He said he was working on his research.

“I’m sure there will be some decline, but it’s not as hypothesized based on crude oil data, and it’s not just a blame,” Dr. Barriser said. “We are now trying to understand it in a clean way.”

Israeli data suggest possible reduced efficacy of Pfizer vaccine

Source link Israeli data suggest possible reduced efficacy of Pfizer vaccine

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