Opinion – Esper Kallás: A pandemic within a pandemic

As if the pandemic’s surprises weren’t enough, the arrival of the omicron has called into question some concepts that had been consolidating since the discovery of Sars-CoV-2.

The main thing is its transmission capacity. Surveillance surveys have shown that, in places where the omicron has entered, it has managed to dominate the transmission chain in the community with impressive speed. Very quickly, it jumps from the condition of sparse cases to most of the identified variants. For example, in the United States, omicron is already responsible for more than 70% of Covid-19 cases, accounting for 3% of them two weeks earlier.

Although still preliminary data, the numbers suggest that transmission seems to respect vaccine protection less. There are increasing reports of people who, even vaccinated with a full regimen, show symptoms and test positive.

Vaccines continue to have an excellent protection profile for the severe form of the disease. The vast majority of people with Covid-19 who need hospitalization are unvaccinated or with an incomplete vaccination schedule. The pattern seems to persist for Covid-19’s initial information caused by the omicron.

There are still doubts about how much vaccines protect against asymptomatic infection or against mild forms of Covid-19, that is, cases without the need for hospitalization.

Blood obtained from vaccinated people shows reduced ability to neutralize the omicron compared to other variants. This difference is much smaller when considering the addition of the third dose of the vaccine. Therefore, at least in the laboratory, omicron seems to require a vaccination schedule with more doses. This preliminary evidence has supported many health managers in accelerating or anticipating the campaign for the additional dose, which some call a booster dose.

A more recent discussion concerns the review of the primary objective of fighting the pandemic. With omicron, would it be appropriate to focus efforts on the prevention of hospitalizations, that is, focus on evaluating the effectiveness of vaccines in preventing serious cases?

Some might imagine that the requirement of proof of vaccination would become less relevant under this argument, but the opposite is true. Under the hypothesis that vaccines might not be as effective in preventing the virus from circulating, vaccination becomes even more important to prevent hospitalizations. In other words, it is those who are not vaccinated or with incomplete vaccination who will occupy hospitals, create an additional burden for the health service and its professionals, and demand greater expenses from public and supplementary health.

Many continue to insist that the Covid-19 caused by the omicron is lighter. There is still not enough evidence to support this. With the majority of the population vaccinated, there is no way to compare cases of Covid-19 in people who received two or three doses of vaccine with the disease in 2020 or early 2021, when the vaccine was not available or had very limited access.

The risk of becoming infected can be high for people with comorbidities and, especially, for people who are unable to mount a protective response after vaccination, such as transplant patients or patients using immunosuppressants.

While in doubt, caution is advised. After all, the beginning of 2021 is still in Brazilian memory, right after the end-of-the-year festivities.

The omicron transmission force appears to have generated a new pandemic within the Covid-19 pandemic. How much we’ve learned and how much we’re prepared is on test.