No one is in any doubt that the Covid-19 vaccines, which have worked so well to contain the pandemic, will need to be updated as the virus mutates. However, the truth is that it is not known for sure how or when. The first generation of immunizations, made from the initial version of the coronavirus (SARS-CoV-2), was a success capable of significantly reducing the number of severe cases and deaths worldwide. It can be said that it was thanks to them that life began to return to normal on the planet.
However, the speed of the virus’ mutations and the immune system’s response now pose a new challenge to science: What should the next generation of vaccines look like? How many doses to apply? Who should be immunized? If, on the one hand, scientists agree that they will need to be updated, the truth is that it is not known for sure how this should be done.
Recently, for example, the FDA approved an update to the vaccine manufactured by Moderna, but with two dissenting votes. That’s because the antibodies of this new version ended up generating a stronger response against the previous variant. That is, although it continues to protect against the mainly serious infection, the silver bullet against the new strains has not yet been shown.
The emergence of the omicron variant showed that the virus is able to bypass the vaccine-induced immune response and even the previous infection itself. So it can be assumed that a new version of Covid-19 could evade new immunizers. Worse still if the mutation results in a virus very different from the ones circulating so far.
“I believe that vaccines should be adjusted, the booster needs to be adjusted, but the truth is that data are still lacking,” says Luiz Vicente Rizzo, an immunologist at Hospital Israelita Albert Einstein. “As the vaccines worked very well initially, the world got used to this level of deaths and they stopped doing research at the speed that was being done”, he adds.
According to him, we still need more studies showing how long the immunity induced by the vaccine lasts, how they behave in the face of new variants, how to achieve a broader response. Not to mention that we are still looking for a formula that, in addition to preventing the disease, is able to prevent the person from infecting others. “All this needs carefully designed studies to control for all the variables involved. It’s not enough to do an observational study looking back to draw conclusions,” says Rizzo.
To get an idea, if we only take into account who gets sick, we have no way of knowing the effectiveness of the booster dose without evaluating, for example, whether those who vaccinated also adopted more protective measures (mask use, isolation, etc). Or if, on the contrary, these people have become more confident and careless – which would mean that the vaccine works even better than expected.
Vaccines in Brazil
Currently, Brazil has four vaccines in use to combat the disease: Coronavac (manufactured by Butantan), Astrazeneca/Fiocruz, Janssen and Pfizer, and the 4th dose (second booster) is being administered to the adult population.
Today there are about 170 million people fully vaccinated — representing 79% of the population — and only 7% partially. This means that 86% of Brazilians went through the vaccination posts. More than half, 53%, received at least one booster dose. So far, more than 465 million doses have been applied, with 350 million in the initial protocol and 150 million as a booster, according to data from the Our World in Data website. If at the beginning of April of last year we had about 14 new deaths per million people, by the end of July 2022 that number had dropped to just over one.
Research is ongoing, testing new vaccine combinations in a range of variants. And two new labs have entered the game: Sanofi Pasteur and GSK. But the answers to these questions only time – and a lot of research – will give us.
Despite all the doubts of scientists, one thing remains certain: any vaccine is better than none. And, while we haven’t arrived at the ideal formula, the versions that are there are the best protection against serious cases and deaths.
#Development #vaccines #covid #lack #data