The agency and European Center for Disease Prevention and Control said that combining vectored vaccines, like Johnson & Johnson's, and mRNA vaccines, like those from Pfizer and Moderna, can produce "good levels of antibodies" that help ward off the virus.
It said heterologous vaccination can in some cases produce even higher T-cell responses than receiving doses of the same vaccine.
The EMA said that, for example, patients can safely receive the mRNA vaccine from Pfizer during initial inoculation and then a vector vaccine from Johnson & Johnson (pictured) as a booster dose. File Photo by Etienne Laurent/EPA-EFE
The EMA noted, however, that its studies looked at using different vaccines for primary inoculation and the later booster. Using different vaccines between the first and second doses of initial vaccination, it said, has been less studied.
The EMA recommendation comes as Europe is seeing rising COVID-19 cases due to multiple variants, including the newly discovered Omicron mutation.
"Vaccines are continuing to prevent many millions of EU citizens from becoming very ill or dying and figures show that numbers of hospitalizations and deaths remain lowest in those member states with the highest vaccination rates," the EMA said in a statement Tuesday.
"While research is ongoing to provide more evidence on long-term safety, duration of immunity and effectiveness, the use of heterologous schedules may offer flexibility in terms of vaccination options, particularly to reduce the impact on the vaccine rollout should a vaccine not be available for any reason."