Pfizer's covid-19 vaccine provided a strong shield against hospitalization and more severe disease in cases caused by the contagious delta variant in Israel in recent weeks, even though it was just 39% effective in preventing infections, according to the country's health ministry.
The vaccine, developed with German partner BioNTech, provided 88% protection against hospitalization and 91% against severe illness for an unspecified number of people studied between June 20 and July 17, according to a Thursday report from the health ministry.
The data could be skewed because of different ways of testing vaccinated groups of people versus those who hadn't been inoculated, the report indicates.
"The heavily skewed exposure patterns in the recent outbreak in Israel, which are limited to specific population sectors and localities," means the analysis may not be able to take all factors into account, said Ran Balicer, chairman of Israel's national expert advisory team on covid-19 response. "We are trying to complement this research approach with additional ones, taking additional personal characteristics into account. But this takes time and larger case numbers."
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Still, the data are likely to fuel debate over whether booster shots should be given to people who've already been vaccinated -- something Pfizer has said it plans to request in the U.S. Israeli authorities said this month they'll give a third round of shots only to people with weakened immune systems.
The data out of Israel, which had earlier access to vaccines than most anywhere else in the world, contrasts with a study out of the U.K. That paper, published this week in the New England Journal of Medicine, found that two doses of the Pfizer-BioNTech vaccine offer 88% protection against symptomatic disease caused by the delta variant and 94% against the alpha variant that was first discovered in Britain.
Public Health England also previously found that the Pfizer-BioNTech shot was 96% effective against hospitalization.
Pfizer and BioNTech are confident in the protection and safety of the two-dose vaccine, a Pfizer statement read Friday. BioNTech is conducting a review of study data on the vaccine, a spokeswoman said.
Analysis of the companies' more than 43,000-person clinical trial shows that effectiveness against symptomatic infection dips over time, from 95% in the first two months to the low- to mid-80% range four to six months after the second dose, Pfizer said.
The delta variant first emerged in India and is spreading around the globe, sometimes infecting those already fully vaccinated. The mutation has prompted some countries to step up inoculation campaigns and rethink plans to loosen curbs on businesses, activity and travel.
MODERNA FOR KIDS
On Friday, the European Medicines Agency recommended authorizing Moderna's vaccine for children 12-17 years old, the first time the shot has been authorized for people younger than 18.
The EU drug regulator said research in more than 3,700 children 12 to 17 showed that the Moderna vaccine -- already given the OK for adults across Europe -- produced a comparable antibody response.
Until now, the Pfizer-BioNTech vaccine has been the only option for children as young as 12 in North America and Europe. The U.S. Food and Drug Administration is currently considering whether to extend the use of the Moderna vaccine to the same age group.
With global vaccine supplies still tight, much of the world is struggling to immunize adults. The World Health Organization and other agencies have urged rich countries to donate doses to the developing world -- where fewer than 2% of people have been vaccinated -- rather than moving on to inoculate their less vulnerable populations.
Hundreds of millions of Moderna doses already have been administered to adults, and the company reports the two-dose vaccine is just as protective for adolescents.
In a study of more than 3,700 12- to 17-year-olds, the vaccine triggered the same signs of immune protection, and no covid-19 diagnoses arose in the vaccinated group compared with four cases among those given dummy shots. Sore arms, headache and fatigue were the most common side effects in the young vaccine recipients, as with adults.
U.S. and European regulators caution, however, that both the Moderna and Pfizer vaccines appear linked to an extremely rare reaction in teens and young adults -- chest pain and heart inflammation.
In the United States, children represent about 14% of the nation's total coronavirus cases to date. While the young are far less likely than the old to get seriously ill, at least 344 children have died of covid-19 in the U.S. alone, according to a tally by the American Academy of Pediatrics.
So far in the U.S., just under half the population is fully vaccinated -- with the highest rates, not surprisingly, among older adults.
Just a quarter of 12- to 15-year-olds, who got access to Pfizer's vaccine starting in May, have had their second dose, according to the Centers for Disease Control and Prevention. Among those 16 and 17, about 37% are fully vaccinated.
Both Pfizer and Moderna have begun testing in even younger children, from age 11 down to 6 months old. These studies are more complex: Teens receive the same dose as adults, but researchers are testing smaller doses in younger children.
The first results from children of elementary school age are expected in September.
Information for this article was contributed by Yaacov Benmeleh of Bloomberg News (TNS); and by Maria Cheng and Lauran Neergaard of The Associated Press.