The word “endemic” has become one of the most misused in a pandemic. And many of the false assumptions made promote misguided complacency. It does not mean that COVID-19 ends naturally.
For epidemiologists, endemic infections are infections whose overall infection rate is static. It does not rise or fall. More precisely, the proportion of people who are likely to get sick is the “basic reproduction number” of the virus, that is, the individuals who are infected, assuming a population where everyone can get sick. It means that it is balanced with the number of. Yes, the common cold is endemic. So are Lassa fever, malaria and polio. Smallpox was so until the vaccine counteracted it.
In other words, the disease is endemic and can be endemic and fatal. Malaria killed more than 600,000 people in 2020. In the same year, 10 million people became ill with tuberculosis and 1.5 million died. Endemic certainly does not mean that evolution somehow tames pathogens and that life simply returns to “normal.”
As an evolutionary virologist, it frustrates me when policymakers call the word endemic as an excuse to do little or nothing. Global health policies go beyond learning to live with endemic rotavirus, hepatitis C, and measles.
To state that an infectious disease becomes endemic affects how long it takes to reach stagnation, what will happen to the case rate, morbidity or mortality, or, decisively, how much of the population and which sector. I don’t say anything about being vulnerable. Nor does it imply a guarantee of stability. A devastating wave of endemic infections may still exist, as seen in the 2019 US measles outbreak.
Immediately after the emergence and spread of alpha variants in late 2020, virus evolution is fast, unpredictable, and even more mutants with different, potentially more dangerous biological properties, unless infection is suppressed. Insisted that it would appear. Since then, public health systems have struggled under highly contagious and more toxic delta variants. Currently, there are Omicrons with substantial ability to evade the immune system, causing reinfection and breakthroughs. Beta and gamma were also very dangerous, but not spread to the same extent.
The same virus can cause endemic, epidemic, or pandemic infections. It depends on the emergence of viral variants, in addition to population behavior, demographic structure, susceptibility and immune interactions. Various conditions around the world can lead to the evolution of more successful variants, which can trigger new epidemic waves. These species are linked to local policy making and the ability to respond to infections. Even if an area reaches equilibrium (even in areas with low or high illness and death), the arrival of new variants with new characteristics can prevent it.
Of course, COVID-19 is not the world’s first pandemic. The fact that the immune system has evolved to cope with constant infections, and the traces of viral genetic material embedded in our own genome from ancient viral infections, are evidence of such an evolutionary battle. Some viruses may be “extinct” on their own and still cause high mortality along the way.
There is a widespread rosy misconception that viruses evolve over time and become more benign. This is not the case. There are no planned evolutionary consequences of the virus becoming more benign. In particular, there are no results such as SARS-CoV-2, where most infections occur before the virus causes a serious illness. Consider Alpha and Delta to be more toxic than the strains first discovered in Wuhan, China. The second wave of the 1918 influenza pandemic was far more deadly than the first.
Much can be done to shift the evolutionary arms race in the favor of humankind. First, you need to set aside lazy optimism. Second, we must be realistic about possible levels of death, disability and illness. When setting reduction targets, it is necessary to consider the risk that circulating viruses will spawn new variants. Third, you need to use formidable weapons that are available worldwide. To gain a better understanding of effective vaccines, antivirals, diagnostic tests, and how to stop aerial viruses by wearing masks, distance, ventilation and filtration. Fourth, we need to invest in vaccines that protect against a wider range of mutations.
The best way to prevent the emergence of more, more dangerous, or more contagious variants is to stop the unrestricted spread, which decisively involves vaccine fairness, Many integrated public health interventions are needed. The more replicated the virus, the more likely it is that a problematic variant will occur. Probably the place with the greatest spread. Alpha variants were first identified in the United Kingdom, Delta was first discovered in India, and Omicron was discovered in southern Africa. This is everywhere where the spread is widespread.
It is no mistake to think that the epidemic is mild and inevitable. It’s dangerous. It launches humanity for years of illness, including waves of unpredictable outbreaks. It is more productive to think about how bad things will happen if we continue to give the virus the opportunity to betray us. Then you might do more to prevent this from happening.
Competing profits
The author does not declare competing interests.
