UK study: Pfizer, AstraZeneca vaccines offer protection against Delta variant

A British study released on Monday found that the Pfizer-BioNTech and AstraZeneca COVID-19 vaccines offer solid protection against hospitalization due to the Delta variant, which recently became the dominant strain in the country. 

Public Health England determined that the full two-dose Pfizer-BioNTech vaccine offers 96 percent protection against hospitalization, and the AstraZeneca vaccine gives 92 percent protection against hospitalization.  

The preprinted analysis concluded that the protection rates are “comparable” to the vaccines’ effectiveness against the Alpha variant. 

The analysis involved 14,019 people in England infected with the Delta strain, including 166 who were hospitalized, between April 12 and June 4. 

Public Health England said more research was needed to determine the mortality rate from the Delta variant. 

Mary Ramsay, the head of immunization at Public Health England, said in a release that the “hugely important findings” show the vaccines give “significant protection” against hospitalization from the Delta strain.

“It is absolutely vital to get both doses as soon as they are offered to you, to gain maximum protection against all existing and emerging variants,” she said.

The Delta variant, also known by the scientific name B.1.617.2, was first discovered in India before it spread to at least 74 countries, including the United Kingdom, where it overtook the Alpha variant to become the dominant strain. 

Another analysis in Scotland published as a letter Monday in the Lancet medical journal concluded that the vaccines were slightly less effective against infection with the Delta strain than other variants. But protection against serious illness was similar to other strains in the analysis of 19,543 cases.  

The Pfizer-BioNTech vaccine was found to give 92 percent protection against the Alpha strain and 79 percent against the Delta variant. The analysis determined the AstraZeneca vaccine was 73 percent effective against Alpha and 60 percent against Delta, after both doses.

The studies were released as concerns have mounted about the Delta variant as it spreads.

An earlier preprint study from Public Health England found that two doses of Pfizer-BioNTech or AstraZeneca were 88 percent and 60 percent effective against symptomatic Delta cases, respectively. But the vaccines gave 33 percent protection to partially vaccinated people with both vaccines. 

British Prime Minister Boris Johnson declared that the planned relaxation of coronavirus restrictions for June 21 would be pushed back up to four weeks as the U.K. sees growing Delta cases.

President Biden’s chief medical adviser Anthony Fauci said last week that more than 6 percent of sequenced U.S. COVID-19 infections were from the Delta variant. He also warned that it was “essentially taking over” the U.K.