World News: Israel Data Suggest Shot Less Effective

"TEL AVIV -- Data from Israel suggests Pfizer Inc.'s vaccine has become less effective in preventing infection of Covid-19 in recent weeks, although it remains a robust bulwark against serious illness as governments around the world scramble to respond to the spread of a new Delta variant.

The findings, which are preliminary and based on a small sample, suggest that after two shots the vaccine was 39% effective at reducing the risk of infection and 40% effective at reducing the risk of symptomatic disease during a period when the Delta variant dominated cases in Israel, according to the country's Health Ministry. The vaccine was 91% effective at preventing severe illness in the same period between June 20 and July 17, the ministry said.

"It's important to say that in terms of protecting against severe illness, hospitalization and death, the Pfizer vaccine is still very very efficient," said Nadav Davidovitch, a member of the expert advisory panel to the Israeli government on the coronavirus. "We are still not sure about whether the reduction in effectiveness is due to time passed or [a] question of the variant."

Mr. Davidovitch said the data was based on hundreds of cases and should only be considered preliminary.

Pfizer said the company and its partner BioNTech SE are confident in the protection and safety of the two-dose vaccine, which it said prevents severe disease and hospitalizations. Two doses continue "to be highly efficacious in preventing Covid-19, including variants and to date, no variant, including Delta, appears to have escaped the protection of the vaccine," Pfizer said.

Natalie Dean, an assistant professor in the Department of Biostatistics & Bioinformatics at Emory University, said not enough is known to draw firm conclusions from the study. The time from vaccinations in January is not very long, and such a major drop would need to be replicated, Dr. Dean said. "It's just such a striking difference and whenever it's like that you always want to see some other verification."

The study may be limited in its ability to ensure the vaccinated groups are compared with similar unvaccinated people, she said. While the study's investigators consider people's ages, sex and time, factors such as occupation, location and whether they live in congregate settings aren't accounted for.

Israel used the Pfizer vaccine to conduct a world-leading campaign that offered glimpses of how governments might combat the pandemic.

The new Israeli data is likely to fuel debate about how soon vaccines lose potency and whether governments should begin administering boosters. Earlier in July, Israel began offering a third dose to immunocompromised individuals, and health officials are studying whether one is necessary for the wider population.

The Israeli Health Ministry has said it calculates the effectiveness of a vaccine by analyzing the number of infections among the vaccinated compared with those who were unvaccinated in the given period. It also accounts for factors such as the week of infection and age, and whether the person was infected in the past.

The ministry said the latest data might be biased because of where coronavirus tests were conducted. Many were carried out in areas of outbreaks and among the elderly, and only a small number of tests were conducted among younger people who were vaccinated. Older Israelis were the first to be vaccinated; many were fully inoculated by the end of January and currently make up the most of cases of severe illness.

Israel's new data suggests a lower potency for the Pfizer shot than was found by another major U.K. study published this week. Published in the New England Journal of Medicine and sponsored by Public Health England, the study involved nearly 20,000 people and said the vaccine was 88% effective at protecting against symptomatic disease." [1]

Given that many young people with mild illness of  Covid receive long-term Covid, the declining effectiveness of the vaccines is bad news for those young people. We need to go back to wearing masks indoors where there are a lot of outsiders.

1. World News: Israel Data Suggest Shot Less Effective
Jones, Rory; Lieber, Dov. Wall Street Journal, Eastern edition; New York, N.Y. [New York, N.Y]24 July 2021: A.8.