Reacción a "Reaction to the EMA recommendation for the use of the Novavax vaccine"

This vaccine is the first vaccine approved in Europe or the U.S. that is based on a protein, a technology used in many other vaccines, such as influenza.

This vaccine consists of protein S in its prefused form and with the furin cleavage site removed, which is expressed in insect cells, purified and mixed with an adjuvant to boost the immune response.

In the case of the other covid-19 vaccines that are approved in Europe or the U.S. the adjuvant is not necessary because either the messenger RNA envelope (Pfizer or Moderna) or the viral vector (AstraZeneca or Janssen) performs the function of the adjuvant.

The Novavax vaccine is delivered in two intramuscular doses of 5 µg protein S + 50 µg adjuvant.

The vaccine has been tested in several clinical trials in the UK, USA and Mexico, in total comparing more than 24,000 vaccinees with more than 15,000 placebo recipients.

The clinical trials have involved people aged 18 to 64 years and over 65 years. In the U.S.-Mexico trial they found 63 symptomatic infections in the placebo group versus 14 in the vaccinated group. And in the UK trial they found 96 symptomatic patients in the placebo group and 10 in the vaccinated group. Therefore, the efficacy of the vaccine has been estimated at around 90 % in preventing symptomatic infection, and higher in preventing severe disease.

In summary, this vaccine is based on a technology long known in the field of vaccines, is safe and effective in preventing symptoms caused by the variants circulating at the time of the trial (mainly alpha and beta). An advantage of this vaccine is that it does not require ultracold, so it could be more easily distributed to parts of the world where other vaccines are difficult to reach.