Do individuals who got inoculated at the beginning of the COVID-19 vaccination campaign – just a little over six months ago – need to get another shot? Not so fast, according to Prof. Cyrille Cohen, head of the immunology lab at Bar-Ilan University.
Cohen warned that such a medical decision cannot be made based on press statements, but rather on verified scientific data – which at the moment is still not available.
At the end of last week, Pfizer’s chief scientific officer Mikael Dolsten said the recently reported dip in the vaccine’s effectiveness in Israel was mostly due to infections in people who had been vaccinated in January or February.
“The Pfizer vaccine is highly active against the Delta variant,” Dolsten said in an interview. But after six months, he said, “there likely is the risk of reinfection as antibodies, as predicted, wane.”
Data will be submitted to the FDA within the next month, he said.
Pfizer did not release the full set of Israeli data on Thursday, but said it would be published soon.
“It’s 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,” Dolsten said.
However, until this information is fully available and reviewed by relevant experts, the conversation is premature and can send the wrong message to the public, Cohen said.
“I think there have been conflicting reports and we need to go more in depth,” he said.
“It is important to remember that first of all, we do not know what they exactly mean when they say ‘people who got vaccinated at the beginning of the campaign,’” Cohen said. “In general, most of them were individuals over 60, who tend to have a weaker immune system and... are also at risk of a severe case of COVID.
“Based on all of this, inferring that there is a drop in immunity is a bit far-fetched, also considering that we are dealing with a new and more contagious variant.”
He stressed that immunity is not only based on antibody level but also on cellular memory.
According to Cohen, all actors involved should be cautious before making statements.
“Statements should be backed by data,” he said. “The data we have so far, both from the Israeli healthcare providers and from Pfizer, suggest that the protection lasts more than six months. Decisions cannot be made based on press releases, as the FDA and the CDC have also said.”
The US Food and Drug Administration and the Centers for Disease Control and Prevention noted in their joint statement that: “We are prepared for booster doses if and when the science demonstrates that they are needed.”
Data needs to be both gathered and analyzed, Cohen said. In addition, when addressing public opinion, things have to be explained well in order to avoid confusion.
“Otherwise, there is a risk of discouraging people who are undecided on whether to get vaccinated, and might think it is not useful,” Cohen remarked.
The evaluation might change after Pfizer publishes the complete set of data regarding the need for a third shot in order to ask for authorization from the FDA.
Asked about Israel’s decision to give a booster to immuno-compromised patients, the professor responded that he thinks it’s a good idea.
“We are talking about people who were born with a defective immune system, who underwent organ transplants and so on, and we have data that shows that the level of protection they have after the vaccine is low,” Cohen said.