Two doses of Pfizer and AstraZeneca coronavirus vaccines are effective against delta variant, study says

Two doses of Pfizer and AstraZeneca coronavirus vaccines are effective against delta variant, study says

By Erin CunninghamToday at 5:18 a.m. EDT

A full course of two of the most widely available coronavirus vaccines is about as effective against the more contagious delta variant as it was against a previously dominant version of the virus, according to a new study published in the New England Journal of Medicine.

Two doses of the Pfizer-BioNTech vaccine offer 88 percent protection against symptomatic disease caused by the delta variant, compared to 94 percent against the alpha variant that was first discovered in Britain and became dominant across the globe earlier this year, the study said.

A double dose of the Oxford-AstraZeneca vaccine was 67 percent effective against delta, according to the British researchers, down slightly from an efficacy rate of 75 percent against the alpha variant.

Here are some significant developments:

  • China said Thursday that it will not accept the World Health Organization’s suggested plan for the second phase of investigation into the origins of the coronavirus. A senior Chinese health official criticized the agency’s proposal to include the lab-leak hypothesis as a research priority.
  • The United States has extended restrictions on nonessential travel at the borders with Canada and Mexico until Aug. 21. The Department of Homeland Security said the decision was made because of the “continued transmission and spread of [the virus] within the United States and globally.”
  • Australia’s most populous state Thursday reported its highest number of new, locally transmitted cases for the year, even as much of the country remained under lockdown to stem an outbreak of the more contagious delta variant. New South Wales, which includes Sydney, recorded 124 new infections, health authorities said.
  • Tunisia’s president has ordered the military to oversee the country’s coronavirus response as the North African nation battles its worst outbreak of the pandemic. Earlier this week, the health minister was fired for bungling Tunisia’s vaccine rollout as the virus spread.
  • The Tokyo 2020 Organizing Committee announced 12 new coronavirus cases among accreditation holders, including two unnamed athletes who were living in the Olympic Village. Eight athletes have now tested positive since arriving in Tokyo for the Games.

The authors of the new study said a single dose of either the Pfizer-BioNTech or the Oxford-AstraZeneca vaccine was significantly less effective against the delta variant than two doses. One dose of the vaccine developed by U.S. firm Pfizer with German partner BioNTech was just 36 percent effective, the study found, while a single shot of the vaccine from Oxford University and British-Swedish company AstraZeneca offered 30 percent protection.

“Absolute differences in vaccine effectiveness were more marked after the receipt of the first dose,” the authors wrote.

The research confirmed earlier data released by Public Health England that suggested the two vaccines offered similar levels of protection against the delta variant when administered as a full course. It also offered some hope to those nations now struggling to beat back outbreaks caused by the delta variant, which the World Health Organization says has now reached at least 124 countries.

The study stood in contrast to preliminary data made public by Israel’s Health Ministry earlier this month that said the Pfizer-BioNTech vaccine was only 64 percent effective in preventing symptomatic infection caused by the delta variant.

Some public health experts warned that the data from Israel was observational and not the result of a controlled study.

By Erin Cunningham Erin Cunningham is an Istanbul-based correspondent for The Washington Post, covering conflict and political turmoil across the Middle East. She previously was a correspondent at the paper’s bureau in Cairo and has reported on wars in Afghanistan, Gaza, Libya, and Iraq. Twitter

Two doses of Pfizer, AstraZeneca shots effective against Delta variant: study

2 minute read

LONDON, July 21 (Reuters) – Two doses of Pfizer (PFE.N) or AstraZeneca’s (AZN.L) COVID-19 vaccine are nearly as effective against the highly transmissible Delta coronavirus variant as they are against the previously dominant Alpha variant, a study published on Wednesday showed.

Officials say vaccines are highly effective against the Delta variant, now the dominant variant worldwide, though the study reiterated that one shot of the vaccines is not enough for high protection.

The study, published in the New England Journal of Medicine, confirms headline findings given by Public Health England in May about the efficacy of COVID-19 vaccines made by Pfizer-BioNTech and Oxford-AstraZeneca (AZN.L), based on real-world data.

Wednesday’s study found that two doses of Pfizer’s shot was 88% effective at preventing symptomatic disease from the Delta variant, compared to 93.7% against the Alpha variant, broadly the same as previously reported.

Two shots of AstraZeneca vaccine were 67% effective against the Delta variant, up from 60% originally reported, and 74.5% effective against the Alpha variant, compared to an original estimate of 66% effectiveness.Vials with Pfizer-BioNTech and AstraZeneca coronavirus disease (COVID-19) vaccine labels are seen in this illustration picture taken March 19, 2021. REUTERS/Dado Ruvic/Illustration/File Photo

“Only modest differences in vaccine effectiveness were noted with the Delta variant as compared with the Alpha variant after the receipt of two vaccine doses,” Public Health England researchers wrote in the study.

Data from Israel has estimated lower effectiveness of Pfizer’s shot against symptomatic disease, although protection against severe disease remains high.

PHE had previously said that a first dose of either vaccine was around 33% effective against symptomatic disease from the Delta variant.

The full study published on Wednesday found that one dose of Pfizer’s shot was 36% effective, and one dose of AstraZeneca’s vaccine was around 30% effective.

“Our finding of reduced effectiveness after the first dose would support efforts to maximise vaccine uptake with two doses among vulnerable groups in the context of circulation of the Delta variant,” the authors of the study said.Reporting by Alistair Smout; editing by Barbara Lewis

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