European Medicines Agency reviewing safety of mixing Covid-19 vaccinations

The 'mix and match' vaccine process is being studied in three European countries. More data is expected to be submitted shortly for review. File picture

The European Medicines Agency (EMA) is reviewing mixing vaccine types to see if it is a safe and effective way to speed up vaccination rollouts.

This "mix and match" process is being studied in three European countries. More data is expected to be submitted shortly for review.

“Preliminary results from studies in Spain, Germany and the UK suggest a satisfactory immune response and no safety concerns,” a spokesperson for the EMA said.

However, they said it was too soon to make “any definitive recommendations” on what is also known as a heterologous vaccination strategy.

It could mean people getting one shot of the AstraZeneca vaccine, which is an adenovirus vector vaccine, followed by a Pfizer shot which is an mRNA type vaccine. 

'Safe and effective'

“There are good scientific grounds to expect this strategy to be safe and effective when applied to vaccination against Covid-19,” the spokesperson said.

The use of a heterologous vaccination strategy may allow populations to be protected more quickly and make better use of available vaccine supplies.” 

The EMA said speeding up vaccinations is critical, warning: “The Delta variant (B.1.617.2) is a variant of concern that is spreading fast in Europe and may seriously hamper efforts to control the pandemic."

Delta up to 60% more transmissible

Evidence suggests it is 40% to 60% more transmissible than the Alpha variant which hit Ireland in January, and also shows it may be associated with a higher risk of hospitalisation, the EMA said.

In a joint statement with the EMA, the European Centres for Disease Control (ECDC) said it estimated the Delta variant would represent 90% of cases across the region in six weeks. It is already reported to be accountable for 80% of new cases in Ireland.

The ECDC urged countries to adapt vaccine roll-outs in safe ways. In 10 European countries, 30% or more of people over 80 are not yet fully vaccinated, the ECDC vaccine tracker shows. 

“EMA and ECDC re-emphasise the need to ensure that as many people as possible are fully vaccinated against Covid-19,” the statement said.

However, it said it was “too early” to say whether booster shots would be needed as it is not yet known how long protection from vaccines lasts.