Opinion – Atila Iamarino: Will we have another wave of Covid in the coming months?

We’re still on the immunity honeymoon. In recent weeks, we have recorded the lowest number of deaths from Covid since December 2021 – the situation was only better in March 2020. If this trend continued for the next few months, we could even think about the end of the pandemic. But in the absence of measures such as masks, reduction of agglomerations and changes in the ventilation of closed environments, the barrier against the virus that maintains this stability is just our immunity. And the two factors, our immunity and the virus, give signs that the situation may be about to change.

The numbers from Brazil are beginning to show important signs. Reversing the March trend, the proportion of positive tests has started to rise in private labs — a sign that more people seeking tests have the coronavirus. And hospitalizations for Covid are starting to increase in hospitals in São Paulo.

This increase could be a temporary reversal, after holidays and agglomerations. But the latest indicator of Covid, the number of deaths, also started to grow. This stabilization of the fall turning into a slow rise can signal a decline in immunity.

Simply put, our body has two important responses against viruses. Cellular immunity, which is the portion of our immune system that recognizes infected cells and induces their destruction before they make more viruses. This immunity seems to be quite long-lasting against the coronavirus and it must be because of it that we are seeing milder cases among those who have already been immunized. And the immunity of antibodies, which recognize the coronavirus directly and block it, while also signaling to our immune system.

Antibodies are even useful in preventing a new infection. But its production drops over time. Among recovered and vaccinated, it is estimated that around six months after immunization the antibodies have already decreased enough for some people to be infected again. And the omicron induces an even weaker immune response than other variants, which could shorten that interval even further.

At least among those infected by the omicron in December of last year, the 5 months that have passed may already be enough to be vulnerable again. For this factor alone, we could already see a gradual increase in cases. But the virus did not stand still either. In South Africa, where the omicron was first detected, a new wave of cases and hospitalizations is already being seen. This time, caused by new lineages of the omicron called BA.4 and BA.5 that kept changing. According to the latest studies, they can escape immunity against the original micron enough to cause new cases earlier and in even more people. And this escape is 3 to 5 times greater among the unvaccinated.​

If the African country serves as an example of what awaits us, as was the case at the end of 2021, we can expect another sharp wave of cases in Brazil in the coming months. With proportionally fewer hospitalizations, as Brazilians are more vaccinated. But with a lot of damage in any case, on account of those who are absent from work, the elderly who are more vulnerable even vaccinated and those who have not yet been vaccinated – such as children under 5 years old, who have already been especially affected by the omicron.

We are in a great phase of the pandemic. And we can look forward to even better times, with fewer cases and for longer than now. But that should still be punctuated by waves of cases, especially if the federal government continues to slack off on vaccinations.