Countering the Delta variant: Two vaccine doses are highly effective --new study

Two doses of vaccine highly effective against Delta variant, U.K. officials say Experts say it's absolutely vital to get the second dose of a two-dose series vaccine. NBC News

Two doses of the Pfizer-BioNTech or the AstraZeneca Covid-19 vaccines are highly effective against hospitalization from the Delta variant of the coronavirus, according to a new analysis from Public Health England released Monday.

The variant, which was first identified in India, has become the predominant strain in the United Kingdom. A previous analysis from PHE suggested that a single dose of the vaccine was less effective against symptomatic illness caused by the Delta variant compared to the so-called Alpha variant, or B.1.1.7, which swept the U.K. in the winter.

The new analysis found that two doses of the Pfizer vaccine were 96 percent effective against hospitalization from the Delta variant, and two doses of the AstraZeneca vaccine were 92 percent effective.

“The second shot is critical,” said Dr. Paul Offit, a vaccine researcher at the Children's Hospital of Philadelphia. “We know from the phase one studies that the second shot induces a level of virus-specific neutralizing antibodies that’s about tenfold greater than that after the first dose.”

The PHE analysis included 14,019 cases caused by the Delta variant in England — 166 of which resulted in hospitalizations — from April 12 to June 4.

“These vaccines have had all along stunning efficacy at least in this case against hospitalization,” said Dr. Gregory Poland, director of the Mayo Clinic's Vaccine Research Group in Rochester, Minnesota.

U.K. health officials urged residents to get their second dose when it’s their turn.

“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,” Dr. Mary Ramsay, head of immunization at PHE said in a statement. ...