Italians under the age of 60 who received a first dose of the AstraZeneca (AZN.L) Covid-19 vaccine, known as Vaxzevria, can be given a different vaccine when they get their second dose, Italy’s medicine agency Agenzia Italiana del Farmaco A said on Monday.

The second dose after Vaxzevria may be with the Comirnaty or Moderna vaccines.

Last week, Italy’s government restricted the use of the AstraZeneca vaccine to people over the age of 60, after a teenager who had received the shot died from a rare form of blood clotting. read more

“Based on clinical studies published in the last few weeks, AIFA’s scientific committee has decided to approve the vaccine mix,” AIFA said in a statement, adding vaccines developed by Pfizer (PFE.N) and Moderna (MRNA.O) could be administered to people who first got an AstraZeneca jab.

The Technical-Scientific Commission of the Pharmaceutical Agency considered “the changed epidemiological scenario”, “the absence of specific indications” to the contrary by the manufacturers and the “need to allow the vaccination campaign to run smoothly”. The second heterologous dose showed “a significant enhancement of the antibody response and a good reactogenicity profile”. Two foreign studies support the conclusions.

Several Italian regions, including Lombardia and Lazio, had held up vaccinations while awaiting a decision from AIFA on this issue.

Vaccinating people with both the Oxford–AstraZeneca and Pfizer–BioNTech Covid-19 vaccines produces a potent immune response against the virus SARS-CoV-2, researchers conducting a study in Spain have found.

The Delta variant first discovered in India is spreading in Europe. Two vaccine doses protect against Delta much better than one dose. Two doses of Moderna or Pfizer appear to offer more protection against symptomatic infection from Delta than two doses of AstraZeneca.

It isn’t clear, however, that getting a second dose of Moderna or Pfizer after the first dose of AstraZeneca will protect effectively against the Delta variant.