What does “endemic” mean?
Epidemiologists say that a disease is endemic when its presence becomes stable in a particular region, or at least predictable, as with seasonal flu. However, there is no consensus on the conditions for meeting this benchmark. With this broad definition, endemism does not necessarily mean that a disease is rare or common, mild or severe. For example, infection rates may still be high; they just have to stay static. Malaria, which is endemic in dozens of countries, mostly in sub-Saharan Africa, killed more than six hundred thousand people by 2020.
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It is easier to define endemic in retrospect when scientists are capable of it determine a basic level because the disease has reached equilibrium. This may be possible when the general population has protection against the disease, whether from vaccination or previous infection.
What does public health policy look like when a disease becomes endemic?
An endemic disease can still (and often does) require a robust political response. The United States and many other countries encourage individuals to get a flu vaccination each year, and they promote practices such as frequent hand washing and covering of the mouth and nose when coughing or sneezing. For malaria and HIV, which are also endemic, various global initiatives are underway to develop more effective and accessible prevention tools. But the reactions are typically not as intense as those during a pandemic, when rising infections give rise to the type of tight restrictions seen throughout the COVID-19 crisis.
Is COVID-19 becoming an endemic disease?
It’s too early to tell. Various government and industry leaders are promoting political shifts in that direction, but officials from the World Health Organization (WHO) and other health experts warn against treats COVID-19 as an endemic disease. The course of the pandemic has changed rapidly with the advent of new coronavirus variants, which has sent countries that had experienced month-long breaks into a tail of infections and hospitalizations. “We do not understand what the next shoe might be to get rid of with this virus,” Michael Osterholm, University of Minnesota, told CFR.
The world has made significant progress in immunizing against COVID-19, but more than a third of people have not yet received a vaccine dose. At the same time, health experts have expressed concern about the effectiveness of certain vaccines. So there is still a long way to go before one achieves the kind of broad, global protection needed for endemicity.
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Some countries are likely to start treating COVID-19 as an endemic disease before others, and it will depend on infection trends as well as on the social mood. “In terms of when a pandemic is over, it’s really a social concept,” says CFR’s Jennifer Nuzzo. “We do not have an epidemiological criterion for ending a pandemic.” Some experts are already looking to Portugal, which has the highest vaccination rate in Europe, as a model for living with endemic COVID-19; restrictions such as limits for large gatherings have been lifted, but many activities still require vaccination certificates and masks. The new standard for international travel could also mean call back for some requirements while retaining others.
What is the risk of prematurely believing that the pandemic is over?
The predominant risk is that the world will again find itself largely unprepared for a more dangerous variant of the virus, and there is still a possibility that a variant may emerge against which existing vaccines are ineffective. Satisfaction and the passivity of the government contributed to the destructive wave of the delta variant across India in early 2021. The United States was in distortion when the omicron variant spread like wildfire at the end of that year, without adequate tests and other supplies to handle the record high levels of infection. “We have already been burned once,” says Osterholm. “Shall we be burned again by not being prepared?”
What should governments do until the world reaches equilibrium with COVID-19?
There’s a best-case scenario where the omicron increase actually causes the transition to endemic COVID-19, but it’s just a scenario of many. Governments should be prepared to deal with the worst options, such as a case where the world’s current vaccines are unable to defend themselves against a new variant.
WHO continues to advocate for increasing the global vaccination rate as the current pace sets the world at least six months away from being 75 percent vaccinated. Experts, including Nuzzo and Osterholm, also call for more resources to be set aside development of new vaccines, especially genetic material-based (which have been shown to be more effective against new varieties), as well as treatments. Upscaling test capabilities and improving surveillance and surveillance networks are also high on the list, as accurate, regular measurements of infection levels in a community allow officials to implement the most effective response.