Opinion – Atila Iamarino: Good news about the new vaccines against Covid

We have encouraging news to continue to lessen the impact of Covid with vaccines. The two RNA vaccine manufacturers received authorization in the US to distribute millions of doses of new bivalent versions of their own. Here in Brazil, Anvisa analyzes the request of one of them. Both represent an important step in maintaining our immunity.

The fall in immunity that happens over time, especially among the elderly, is remedied by the booster dose. But the relentless accumulation of mutations in the coronavirus causes our immune system, from vaccinated and cured, to lag. As the vaccines available were developed with the original virus from Wuhan in early 2020, this lag is already over two years. The solution is to repeat what we do with influenza—the flu virus.

Influenza vaccines are tetravalent, as they combine four strains of influenza, which have accumulated mutations for decades. The coronavirus has accumulated differences that justify a similar approach in a few years. This makes the Covid vaccine renewal cycle more urgent. So much so that RNA vaccines were able to release updated versions. The simplicity of this type of vaccine, which only carries the information (RNA) for our body to make the spike protein of the virus, which awakens immunity with the greatest potential to prevent the virus from infecting our cells, makes the update process much more practical.

The bivalent Covid vaccines have information to make two spike proteins. One comes from the 2020 coronavirus, as with other vaccines. The other spike comes from the BA.5 lineage of the omicron variant, detected in April 2022. This is the great asset, the two are the first vaccines to include an update with the variant that has dominated infections in the world.

In the case of the flu virus, as soon as important new variants are identified, the immunity produced by new vaccine candidates is tested in mice. The spike of the BA.5 strain of the bivalent vaccine was tested in this way and aroused better immunity than the original strain of the virus or the first omicron variants of November 2021. It is not a direct transposition of what we will see in humans, but it is a model much more agile than waiting for their performance.

The first human trials with updated vaccines for the omicron variant were carried out with the BA.1 strain, but they only gave results when BA.1 had already been replaced by BA.5. And if she took time now, we would only know the results when she was no longer so essential. So every month saved in development is critical. We will only have the results of effectiveness — the effectiveness of vaccines in the real world — over the next few months, when new variants should already cause new waves.

On the other side of the world, in China, another good news: the first vaccine against Covid that is inhaled, instead of needing a needle has been approved. Given as a booster dose, it aroused more antibodies in human volunteers than a third dose of the injectable inactivated vaccine (such as Coronavac). The combination of these two technologies, an updated inhalable RNA vaccine, would be the solution with the greatest potential to stop the virus based on immunization. Especially the elderly and those with conditions such as compromised immune system will benefit from the bivalent vaccine.

Here in Brazil, our challenge is yet another. Convince people to take the vaccines that are already available, from Covid booster doses to traditional vaccines. And convince the Minister of Health to buy enough doses for childhood vaccination against Covid.