In these almost three years of the spread of the Covid-19 virus, we have observed the surprising acceleration of scientific progress, with the development of effective and safe vaccines, therapeutic options (with scientific evidence) and the validation of tactics whose probabilities point to a successful strategy. for the control – and the exit – of a pandemic. The scenario that points to the exit from the pandemic seems to be taking shape: the prospect of an endemic disease.
Generally speaking, when an infectious agent becomes endemic in a population, a recurrent pathogen occurs, the overall rates of which are static – neither increasing nor decreasing. That is, the number of individuals that an infected person can contaminate, also called the basic reproduction number of the virus, is very close to 1: each case generates, on average, a new case. For us, who live at a time when these values are much higher, this proportion could sound practically harmless, even desirable. Unfortunately, there is nothing harmless about an endemic.
To understand what an endemic disease is, it is necessary to remember the current diseases that fit into this category. In 2020, malaria killed more than 600,000 people in Africa; in the world, around 10 million individuals were affected by tuberculosis, of which 1.5 million died from this disease. Many of these endemic conditions become more serious, especially in low-income countries, with precarious sanitary and health conditions. In the words of virologist Aris Katzourakis, “endemic certainly does not mean that evolution has somehow ‘tamed’ a pathogen so that life simply returns to normal.” For Katzourakis, proclaiming the proximity of an endemic scenario at this moment can encourage a misguided complacency, exempting decision-makers from a more incisive action on our reality.
Public health policies must continue to be based on available scientific knowledge, with coordinated actions that promote the advancement and expansion of vaccination, the use of adequate masks, in addition to physical distancing and the preference for open and well-ventilated environments. Once this protocol has been established and followed, which has already been widely publicized by the media, we will be able to determine a possible form of the Covid-19 endemic. What is done now will be crucial to the way we live this endemic.
The current situation can also direct us to a path that will preserve the pandemic: the high transmission observed by the presence of new variants of the virus brings risks even to regions with greater vaccine coverage. Even if a region reaches an equilibrium – whether with low or high numbers of cases and deaths – this stability can be disturbed with the emergence of a new variant, with new characteristics. It’s not the first pandemic we’ve faced, but it seems we still haven’t learned from our history.
The thought that endemicity is mild and inevitable is dangerous, as we may have to face many years of disease and unpredictable waves of new cases. We need to understand that the safest way is not to give the virus opportunities to transmit itself, as it will always seek an adaptation. In doing so, we will invest in the best possible strategy: preventing a worst-case scenario from happening.
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Mellanie Fontes-Dutra, biomedical, researcher at the Federal University of Rio Grande do Sul (RS) and coordinator of the Covid-19 Analysis Network.
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