As the number of COVID-19 cases globally are on the rise, health experts are contemplating to administer fourth dose of the vaccine to fight the virus and boost immunity. However, European health officials argue that it would be too early to consider giving a fourth dose of messenger RNA (mRNA) coronavirus vaccines to people. But they also say that an extra booster can be administered to those over age 80.

In a joint statement on Wednesday, the European Medicines Agency (EMA) and the European Center for Disease Prevention and Control (ECDC) said they had reviewed data for a fourth dose of the COVID-19 vaccines made by Pfizer-BioNTech and Moderna Inc. They included real-world data from Israel, where research has shown that a second booster provides only marginally higher protection.

"There is currently no clear evidence in the European Union that vaccine protection against severe disease is waning substantially in adults with normal immune systems aged 60 to 79 years," the agencies said. But the organizations acknowledged that if the pandemic situation changes, it might be necessary to consider a second booster dose in that age group.

For adults younger than 60 with no underlying health issues, "there is currently no conclusive evidence that vaccine protection against severe disease is waning or that there is an added value of a fourth dose," the EMA and ECDC said.

The advice stands in contrast to guidance issued by the U.S. Food and Drug Administration, which decided last week that Americans 50 and older can get a second COVID-19 booster if it's been at least four months since their last vaccination.

The U.S. Centers for Disease Control and Prevention later recommended the extra shot as an option but stopped short of urging that those eligible rush out and get it right away. That decision expands the additional booster to millions more Americans.

The European recommendations come as numerous countries across the continent have dropped nearly all their COVID-19 restrictions and are battling a surge of the disease fueled by the hugely infectious omicron subvariant BA.2. The variant's milder disease has not driven up hospitalizations and deaths as in previous waves and authorities in many countries hope their high immunization rates will ward off any major disruptions to society.