Will COVID-19 Become Endemic?

Check out this answer from Consensus:

While it is challenging to predict the exact trajectory of COVID-19, the evidence suggests that SARS-CoV-2 may become an endemic virus, similar to other respiratory pathogens. The transition to endemicity will depend on factors such as reinfection, seasonality, public health measures, and the evolution of the virus. Preparing for this scenario will require sustained efforts in vaccination, surveillance, and public health interventions to manage the ongoing impact of COVID-19 on global health.

The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a profound impact on global health, economies, and daily life. As the world continues to grapple with this virus, a critical question arises: will COVID-19 become endemic? This article explores the potential for COVID-19 to transition from a pandemic to an endemic state, examining the factors that influence this transition and the implications for public health.

Understanding Endemicity

Endemicity refers to the constant presence and/or habitual prevalence of an infectious agent within a specific geographic area or population. Unlike a pandemic, where the disease spreads rapidly across countries and continents, an endemic disease is stably maintained within a population over time1. The transition from an epidemic to an endemic state involves changes in the number of infections and the severity of the disease, influenced by factors such as immunity, viral mutations, and public health interventions1.

Factors Influencing Endemicity

Several factors will determine whether COVID-19 becomes endemic:

Reinfection and Immunity

Reinfection, where individuals experience multiple infections from the same virus over their lifetime, is a common feature of many respiratory viruses, including influenza and endemic coronaviruses. The persistence of SARS-CoV-2 in the human population may be driven by its ability to cause reinfections, especially if immunity wanes over time or if the virus undergoes antigenic changes that diminish immune protection2 6.

Seasonality and Viral Competition

Seasonal patterns and competition with other respiratory viruses, such as influenza and respiratory syncytial virus (RSV), will also shape the endemic transmission of COVID-19. Nonpharmaceutical interventions (NPIs) like social distancing have already impacted the transmission dynamics of these viruses, potentially leading to larger outbreaks in the future as susceptibility increases5.

Public Health Measures

The implementation and effectiveness of public health measures, including vaccination campaigns, will play a crucial role in controlling the spread of SARS-CoV-2. While vaccines are expected to reduce the severity and incidence of COVID-19, the virus may still persist in pockets of susceptible individuals, leading to localized outbreaks3 6.

Implications of Endemic COVID-19

The transition to endemicity has significant implications for public health, healthcare systems, and society at large:

Healthcare System Burden

Endemic COVID-19 will require ongoing management and surveillance to prevent and control outbreaks. This includes maintaining healthcare capacity to handle periodic surges in cases, particularly during seasonal peaks4 5.

Social and Economic Impact

The constant presence of COVID-19 will continue to affect daily life and economic activities. Public health strategies must balance the need to control the virus with minimizing disruptions to society and the economy3.

Long-term Strategies

Effective long-term strategies will involve continuous monitoring of the virus, updating vaccines to address new variants, and maintaining public health infrastructure to respond to outbreaks. Research into the dynamics of SARS-CoV-2 infection and immunity will be essential to inform these strategies4 6.

 

---

Will COVID-19 become endemic?

Graham Medley has answered Uncertain

An expert from London School of Hygiene and Tropical Medicine in Infectious diseases, Epidemiology

There are a number of coronaviruses which are endemic in humans. This means that there are always people who are infected, who pass infection to somebody else and then recover. Over a long time each person infects on average one other person, so that the number infected remains approximately the same. 

In the UK, endemic coronaviruses are seasonal so that the prevalence (proportion infected) goes up during spring and comes down during the summer. These endemic infections are usually in children causing mild symptoms. Endemic coronaviruses are not associated with significant disease. By the time children are adults they will have been exposed, and potentially infected, many times, and are immune. 

The new coronavirus has only been with us for a few months, so it is impossible to be precise about what will happen. However, it is quite possible that it will follow the same pattern. There are two likely scenarios. First, that infection in very young children does not cause disease (as seems to be the case), and vaccination is not extended to very young children. Eventually, all adults will either have been vaccinated or exposed and the new coronavirus will join the others as a mild respiratory infection in young children. In the future, there will be no adults who are not immune because they were all infected as children. The second scenario is more likely if it turns out that the new coronavirus is causing significant disease in children or is not able to prevent disease in adults. In this case, vaccination might be extended to the very young. This might result in the virus being eliminated from the population, if the vaccine is able to prevent people becoming infected. If the virus is able to continue transmitting within a vaccinated population, then it will remain endemic, but vaccines will prevent the great majority of disease. We do not know which scenario is more likely because we do not know how the coronavirus, and future variants of the coronavirus, will interact with the vaccine, and future versions of the vaccine.

 

Will COVID-19 become endemic?

James Wood has answered Near Certain

An expert from UNSW Sydney in Epidemiology, Infectious diseases, Public Health

This remains a challenging question that depends on the nature and duration of immunity following infection from COVID19 and the degree to which we pursue elimination attempts. It seems very likely that, without intervention, SARS-CoV-2 would eventually become endemic and possibly push one or more of the existing human coronaviruses towards extinction. In the parallel situation when pH1N12009 (swine flu) emerged in 2009, it became endemic within a year of the initial pandemic and also pushed the existing H1N1 influenza strain circulating in humans to extinction.

We now have highly vaccines which do raise the possibility of elimination or eradication through achieving high vaccine coverage and herd immunity. However, the limitations in our ability to produce vaccine (15-20 million doses per day) mean that high global coverage with 2 doses will take well over a year even with relatively equitable supply of vaccines. Meanwhile, it’s clear that viral variants that escape existing immunity to some degree have already emerged and can be expected to continue to emerge with regularity. It therefore seems doubtful that we could achieve global eradication through vaccination, due to supply limitations and the rate of viral evolution. In addition, elimination and eradication may not remain as priorities if residual protection from vaccines against severe disease remains strong despite the emergence of variants.

Therefore, I believe it is very likely that COVID-19 will become endemic.

 

Will COVID-19 become endemic?

Adrian Esterman has answered Near Certain

An expert from University of South Australia in Epidemiology

The SARS-CoV-2 virus cannot be eradicated. We now know that vaccination does not provide complete protection against being infected, and those who have already been infected with the virus can be reinfected as immunity wanes, or new variants appear. Finally, vaccine hesitancy will make it more dfficult to achieve herd immunity. The most likely scenario is that people will need regular vaccinations to account for lowered immunity and new variants, and that the virus will become endemic in most countries.

 

Will COVID-19 become endemic?

Adebola T.  Olayinka has answered Uncertain

An expert from World Health Organization in Epidemiology, Public Health, Clinical Research

The dictionary of epidemiology defines an endemic disease as, “the constant presence of a disease or infectious agent within a given geographic area or population group; may also refer to the usual prevalence of a given disease within such an area or group.

I say it is uncertain because we do not have the scientific evidence to support that there is a roadmap of mutations that allow a virus to become endemic.

If we are able to get an effective vaccine over time, there is the possibility of eradication like smallpox if eventually everyone can have access to the vaccine. Of course there is also the possibility or challenge of having some pockets of infection among people who are asymptomatic and may keep spreading it.

So right now it is uncertain

 

Will COVID-19 become endemic?

David Hayman has answered Near Certain

An expert from Massey University in Epidemiology

The coronavirus that causes COVID-19 is affecting 212 countries and territories around the world (https://www.healthmap.org/covid-19/, https://www.worldometers.info/coronavirus/). Only a few countries have put in place sufficient testing, tracing and isolating of cases, along with more strict social distancing to enable the control of the virus. Given the under-reporting due to poor testing capabilities globally (e.g. https://doi.org/10.1016/S0140-6736(20)31053-9) and the pre-symptomatic transmission (e.g. https://doi.org/10.1038/s41591-020-0869-5) this infection is very hard to control. Without sufficient control in every country, the infection is so infectious it will re-surge when social distancing is lifted if it has not been eliminated (e.g. https://science.sciencemag.org/content/early/2020/04/24/science.abb5793)

Update on 28th April 2021: Since writing my first comments above almost a year ago, we now have highly effective vaccines, which is remarkable and means that it is now feasible to eliminate or even eradication SARS-CoV-2 through immunisation. However, it seems very unlikely that eradication will be feasible, at least in the short to medium term. Just a few percent of the world has been vaccinated and SARS-CoV-2 is very infectious. For example, there is exponential growth in the numbers of cases in India at the moment with more than a quatre of a million new cases a day. There is enormous inequality in vaccine distribution, with just a few percent of the world currently vaccinated. This means that unless this is resolved the virus will likely become endemic in those countries. There is the potential for variants to emerge that escape the immunity induced by immunisation or natural infection which may complicate immunisation programmes. And finally, countries which poorly controlled the virus but are now immunising their populations at high rates to achieve suppression of transmission still need to ensure that a large enough part of the population is immune before there is true population level immunity. 

 

Will COVID-19 become endemic?

Lee Riley MD has answered Likely

An expert from University of California, Berkeley in Infectious diseases, Epidemiology, Vaccinology

Over one year into the pandemic, we now know more about how SARS-CoV2 behaves. We now know that the virus mutates faster than we first thought and that we are now seeing emergence of new variants with enhanced transmissibility and maybe virulence. We also have several effective vaccines but some of the variants, although still susceptible, have reduced neutralizability to the antibodies induced by the vaccines. In places where there is a mixture of vaccinated and unvaccinated populations, the vaccines may exert selective pressures on the virus to undergo further mutations, and these variants will spread among the unvaccinated people. Some of the variants may also infect vaccinated people. All of these factors are likely to contribute to COVID19 becoming endemic. We are very likely to enter a new phase when people may need to receive booster vaccines, perhaps not seasonally like the influenza vaccine, but in some phased fashion.

 

Will COVID-19 become endemic?

Jane Heffernan has answered Likely

An expert from University of York in Infectious diseases, Epidemiology

Infectious diseases can become endemic in a population when herd immunity hasn’t been achieved. Herd immunity refers to the fraction of a population that needs to be resistant to infection to an infectious disease in order for the entire population to be protected. We can use the following estimate to calculate this fraction p

p = 1-1/R0

where R0 refers to the reproduction number of the disease. For COVID-19, with a reproduction number between 2.5 and 8 (depending on the variants that dominate the population), p lies in the range of 0.6 to 0.88, meaning that 60-88% of the population must have protective immunity against infection in order for the entire population to be protected. If immunity doesn’t protect against infection, but allows for milder infections, this threshold does not apply. 

COVID-19 infection and vaccination can induce high levels of protective immunity in individuals. The immunity gained can protect against infection, or, if infected, will lessen the severity of disease. COVID-19 vaccination is not currently available for children. Given that immunity does not necessarily protect against infection, and given that children cannot yet be vaccinated, it will be extremely difficult to reach the herd immunity threshold. Thus, COVID-19 will most likely become an endemic disease. However, the severe outcomes of COVID-19 will lessen, since individuals will have immunity that can protect them from these dire outcomes. It is thus likely that COVID-19 will become endemic, but in a mild manner, and will be similar to what the global population already experiences from other coronaviruses which are common and endemic in humans.