The European Medicines Agency (EMA) sees no grounds yet for COVID-19 booster jabs, it says, after Pfizer and BioNTech reported "encouraging data" from an ongoing trial on third vaccine doses.
So far, insufficient data on the protection period had been gathered from studies and vaccination campaigns, EMA responded to a query from the DPA news agency.
Previously, Pfizer and BioNTech said it was "likely, based on the totality of the data we have to date, that a third dose may be needed within 6 to 12 months after full vaccination".
Such data would be quickly evaluated once it was available, EMA wrote, adding that the agency was in contact with the manufacturers regarding boosters, in order to take regulatory steps as quickly as possible, if necessary.
Hours after the Pfizer and BioNTech announcement on Thursday, the US medicines and health authorities issued a rebuttal.
"Americans who have been fully vaccinated do not need a booster shot at this time," the Centers for Disease Control and Prevention (CDC) and the US Food and Drug Administration (FDA) said in a joint statement.
"We are prepared for booster doses if and when the science demonstrates that they are needed," they added, noting that they were engaged in a "science-based, rigorous process" taking into account a slew of data.
Their research "can include data from specific pharmaceutical companies but does not rely on those data exclusively," the FDA and CDC added.
Meanwhile, Pfizer and BioNTech said they are developing an updated version of their COVID-19 vaccine that targets the full spike protein of the Delta variant, AFX reported.
The companies plan to start clinical trials in August of an updated version of their vaccine that would better protect against the Delta variant.