Pfizer Inc.听plans to ask US regulators to authorize a booster dose of its听coronavirus disease 2019 (COVID-19)听vaccine within the next month, the drugmaker鈥檚 top scientist said on Thursday, based on evidence of greater risk of reinfection six months after inoculation and the spread of the highly contagious Delta variant.听
The US Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) said, however, in a joint statement that Americans who have been fully vaccinated do not need a booster COVID-19 shot at this time.听
Some scientists have also questioned the need for booster shots.听
Pfizer鈥檚 chief scientific officer, Mikael听Dolsten, said the recently reported dip in the vaccine鈥檚 effectiveness in Israel was mostly due to infections in people who had been vaccinated in January or February. The country’s health ministry said vaccine effectiveness in preventing both infection and symptomatic disease fell to 64% in June.听
鈥淭he Pfizer vaccine is highly active against the Delta variant,鈥澨齅r.听Dolsten听said in an interview. But after six months, he said,听鈥渢here likely is the risk of reinfection as antibodies, as predicted, wane.鈥听
Pfizer did not release the full set of Israeli data on Thursday, but said it would be published soon.听
鈥淚t鈥檚 a small data set, but I think the trend is accurate: Six months out, given that Delta is the most contagious variant we have seen, it can cause infections and mild disease,鈥澨齅r.听Dolsten听said.听
听The听US Food and Drug Administration (FDA)听and听Centers for Disease Control and Prevention (CDC), in their joint statement, said:听鈥淲e are prepared for booster doses if and when the science demonstrates that they are needed.鈥听
Pfizer鈥檚 own data from the United States showed an erosion of the vaccine’s efficacy to the mid-80s after six months,听Mr.听Dolsten听said, against the variants circulating there in the spring.听
He stressed that data from Israel and Britain suggests that even with waning antibody levels, the vaccine remains around 95% effective against severe disease.听
The vaccine, developed with German partner BioNTech听SE ,听showed 95% efficacy in preventing symptomatic COVID-19 in a clinical trial the companies ran last year.听
Mr.听Dolsten听said early data from the company鈥檚 own studies shows that a third booster dose generates antibody levels that are five-to-10-fold higher than after the second dose, suggesting that a third dose will offer promising protection.听
He said multiple countries in Europe and elsewhere have already approached Pfizer to discuss booster doses, and some may begin administering them before a potential U.S. authorization.听
Mr.听Dolsten听said he believes booster shots are particularly important in older age groups.听
Dr. Eric Topol, a professor of molecular medicine and director of the Scripps Research Translational Institute in La Jolla, California, said basing the decision on waning antibody protection ignores the role of important other parts of the immune response, including memory B cells, which can make antibodies on demand when challenged by the virus.听
鈥淵ou need better studies to be able to assert that. It isn’t just neutralizing antibodies,鈥澨鼶r.听Topol said.听
Pfizer has previously said people will likely need a booster dose, though some scientists have questioned when, or whether, boosters will be needed.听
Pfizer plans to launch soon a placebo-controlled efficacy trial of the booster with 10,000 participants. The study will run throughout the fall,听Mr.听Dolsten听said, meaning it will not be completed ahead of the company鈥檚 filing with the FDA.听
Dr. William Schaffner, a vaccine expert at Vanderbilt University Medical Center, said even if Pfizer succeeds in getting its booster authorized by the FDA, that would be only the first step. The booster would still need to be reviewed and recommended by advisers to the CDC.听
鈥淚t鈥檚 not automatic by any means,鈥澨齢e said.听Dr.听Schaffner said realistically, most of the public health bandwidth in the United States is still focused on encouraging Americans to get their first and second doses of the vaccine.听
Because boosters would drive increasing demand for vaccines while much of the world is still unvaccinated,听Mr.听Dolsten听said Pfizer is looking at ways to boost production.听
It is already targeting production of 3 billion doses this year and 4 billion doses next year.听Mr.听Dolsten听declined to give a forecast of exactly how many more doses the company could add, but said,听鈥淲e can step up billion after billion in听鈥22.鈥听
Mr.听Dolsten听also said Pfizer and BioNTech are designing a new version of the vaccine targeting the Delta variant, but said the companies do not believe that the current version will need to be replaced in order to combat the variant.听
Pfizer expects the COVID-19 vaccine to be a major revenue contributor for years and has forecast sales of $26 billion from the shot in 2021. Global spending on COVID-19 vaccines and booster shots could total $157 billion through 2025, according to U.S. health data firm IQVIA Holdings.听鈥听Michael Erman and Julie听Steenhuysen/Reuters听
