The Pfizer vaccine might not be as effective against the delta variant as we originally thought

pfizer effective delta
Photo via Marco Verch/Flickr (CC BY 2.0)

Results from a Pfizer vaccine study in Israel are showing that the mRNA vaccine may not be as effective against the delta variant as it is against other variants of COVID-19.

As Reuters reported, the latest study results showed that the Pfizer vaccine hasn’t been as effective as previously believed against stopping the delta variant from infecting vaccinated people and causing them to have symptoms. But it is still highly effective in stopping people from getting seriously ill.

The report noted, “Vaccine effectiveness in preventing both infection and symptomatic disease fell to 64% since June 6,” according to Israeli health officials. However, the vaccine was 93% effective in preventing hospitalizations and serious illness from COVID-19, showing some level of effectiveness against the more severe aspects of the delta variant.

Originally, experts said that Pfizer was about 88% effective against the delta variant after two doses (but only about 33% after just one dose).

The Times of Israel reported that “the delta variant, which is believed to be twice as contagious as the original strain of COVID-19, is thought to be responsible for 90% of new cases in Israel over the past two weeks.”

That’s despite, as the Reuters report noted, nearly 60% of Israel’s 9.3 million people getting at least one shot of the Pfizer vaccine in the nation’s ongoing vaccination campaign. That’s allowed the daily case average to drop from more than 10,000 in January to just single digits in June.

As a result, Israel dropped its mask requirements and its social distancing measures, though masking has been partially readopted since the beginning of July. Daily cases are now on the rise again, reaching 343 on July 4—a phenomenon that’s being attributed to the delta variant.

Despite that, though, there’s an indication that the nation won’t return to its prior concerning levels of cases. Reuters sourced data scientist Eran Segal who noted that Israel was unlikely to experience the high levels of hospitalizations seen earlier in 2021 since there were much fewer critically ill.

Segal noted the people there could “continue with life back to normal and without restrictions,” provided that health officials focus on vaccination outreach and testing citizens returning to Israel from trips abroad.

For the time being, those vaccination efforts will just focus on two doses of the Pfizer vaccine, with Isreali health officials clarifying “there is no recommendation or decision at this stage to vaccinate the general public in Israel with a third dose.”

Read more on the delta variant: 

Sources: Reuters, The Times of Israel

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