What does “endemic” mean?
The World Health Organization’s (WHO) announcement on May 5 that COVID-19 is no longer an international public health emergency has raised hopes that the pandemic is on its way to becoming endemic.
Epidemiologists say a disease is endemic when its presence becomes steady in a particular region, or at least predictable, as with seasonal influenza. But there’s no consensus on the conditions for meeting this benchmark. By this broad definition, endemicity doesn’t necessarily mean a disease is rare or common, mild or severe. For example, infection rates can still be high; they just have to remain static. Malaria, which is endemic in dozens of countries, mostly in sub-Saharan Africa, has killed more than six hundred thousand people each year.
What does public health policy look like when a disease becomes endemic?
An endemic disease can still (and often does) require a robust policy response. The United States and many other countries urge individuals to get a flu vaccination each year, and they promote practices such as frequent handwashing and covering one’s mouth and nose when coughing or sneezing. For malaria and HIV, which are also endemic, various global initiatives are ongoing to develop more effective and accessible prevention tools. However, the responses are typically not as intense as those during a pandemic, when surging infections prompt the type of tight restrictions seen throughout the COVID-19 crisis.
Is COVID-19 becoming an endemic disease?
It’s still too early to tell, although there are many encouraging signs. The WHO lifted its PHEIC—or public health emergency of international concern—designation for COVID-19 after more than year of downward trends in hospitalizations and deaths, as well as rising levels of immunity worldwide.
However, ending the PHEIC doesn’t mean the pandemic is over or that COVID-19 has become endemic. The WHO will now transition to making recommendations for the long-term management of the pandemic, acknowledging that risks remain high and that there are uncertainties for its evolution.
Many countries are already loosening pandemic-related restrictions as the spread and severity of COVID-19 declines. The United States officially lifted its federal public health emergency on May 11, 2023, ending the funding that granted free access to testing, vaccinations, and antiviral treatments and allowed for automatic reenrollment in the public insurance plan known as Medicaid. China, which had some of the strictest COVID-19 regulations earlier in the pandemic, has even lifted its more rigid measures. Several other countries, such as Canada, Mexico, Spain, and the United Kingdom, have moved closer toward treating the disease as endemic, leaving almost no major COVID-19 restrictions in place.
What are the risks of prematurely thinking the pandemic is over?
The predominant risk is that the world will again find itself largely unprepared in the face of a more dangerous variant of the virus, and the possibility remains that a variant could emerge against which existing vaccines are ineffective.
Complacency and government inaction contributed to the devastating surge of the delta variant across India in early 2021. And the United States found itself scrambling as the omicron variant spread like wildfire at the end of that year, without sufficient tests and other supplies to manage the record infection levels. U.S. health officials say the majority of Americans have been infected with COVID-19 at least once, but they caution people not to presume they have protection for the future.
What should governments do until the world reaches an equilibrium with COVID-19?
The best-case scenario is that broad immunity from vaccination and previous infections indeed prompt the transition to endemic COVID-19, but that is just one possibility. Governments should be prepared to handle the worst, such as a case in which the world’s current vaccines are unable to defend against a new variant.
The WHO continues to advocate for vaccination, particularly across Africa and parts of the Middle East where small portions of the population are immunized. Experts also urge dedicating more resources toward developing vaccines and treatments and making them more widely available. Scaling up testing capabilities and improving monitoring and surveillance networks are also high on the list, since having accurate, regular measurements of infection levels in a community allows officials to implement the most effective response.
Will Merrow helped create the graphic for this In Brief.