Spain to start clinical trial on mixing COVID vaccines

OVIEDO, Spain

Spain's public epidemiological institute announced on Monday that it will begin a clinical trial to study the effects of combining the AstraZeneca and Pfizer COVID-19 vaccines.

Around 2 million essential workers younger than 60 got the AstraZeneca shot in Spain before the country shifted its strategy. Now, it is only approved for those aged 60 to 69.

Those 2 million people remain in a vaccine limbo – unsure whether they will get a second dose of AstraZeneca, a dose of Pfizer, or no second dose at all.

The clinical trial aims to answer the question of what would happen if the AstraZeneca dose is followed by Pfizer, or if simply one dose of AstraZeneca is enough to generate protective immunity.

According to a press release, combining the two vaccines may even be "desirable, since they are vaccines that act with different mechanisms."

Some countries like France have already started mixing the two, but Spain wants clinical data before making a decision.

According to Spain's Health Ministry, this is one of the world's first clinical trials on COVID-19 vaccine mixing. Around 600 people will take part.

Phase 2 should produce results within five weeks from the beginning of the trial, set to start within the next week.

As Spain continues to hold back AstraZeneca from younger people and has suffered delays with the Johnson & Johnson vaccine, the infection rate continues to slowly rise.

The ministry reported more than 21,000 new infections over the weekend. Six of Spain's regions, including Madrid, Catalonia, Andalusia, and the Basque Country, are now considered to be at levels of extreme epidemiological risk.

There were fewer deaths this weekend than the last, with the pandemic claiming another 121 victims in Spain. Hospitalizations surged, on the other hand, with hospitals treating an extra 750 active COVID-19 patients.

Meanwhile, almost 20% of the population has been vaccinated with at least one jab.