Even with perfect vaccines that offer permanent immunity, eliminating diseases is still incredibly difficult.
The Covid-19 outbreak was first called an epidemic. After a while, it was described as a pandemic. Now, scientists are saying that it could possibly become ‘endemic’.
But what does that mean?
A quick recap. An epidemic is a disease spreading rapidly within a specific area, or region. A pandemic is an epidemic gone global, affecting large numbers of people. An endemic disease means it never really goes away, and often returns in a specific season or region periodically.
More and more leading scientists are warning that in spite of vaccines, the disease could be here to stay.
David Heymann, who led the World Health Organisation’s infectious disease unit during the SARS epidemic in 2002-2003 warned that Covid-19 could end up lingering like other diseases such as HIV, Ebola, Zika and pandemic flu.
Speaking at a virtual Chatham house, Dr. Anthony Fauci, the United State’s leading expert on infectious disease, agreed with Dr. Vallance, and stressed that there may be a need to re-vaccinate people if the disease lingers, while warning, “We need billions [of doses], so whether you live in the darkest part of the developing world, or if you live in London, you should have the same access."
Dr. Fauci’s concern is rooted in hard science and a history of diseases that are incredibly hard to stamp out even with a cure.
Dr. Vallance, also the United Kingdom chief science advisor, explicitly warned the national security committee that the disease could return, much like the flu, with repeated outbreaks.
Other scientists in the Scientific Advisory Group for Emergencies also agree. Even if vaccines “decrease the chance of infection or severity of the disease - this then starts to look more like an annual flu than anything else. That may be the direction we go on.”
What could make Covid-19 go endemic?
There’s a few factors that go into this. First, how high are the risks of reinfection, how available and effective is a vaccine, as well as possible seasonalities of the virus, and interactions with other viral illnesses, which could change the way its spread.
In a scientific article published in the leading academic journal Science, a scenario is presented where immunity to Covid-19 weakens within a year. Why a year? They modelled it based on another animal-transmitted coronavirus that causes mild respiratory illness. If that’s the case, the authors warn, we could see annual outbreaks much like the flu. If immunity lasts longer than a few years however, we could eliminate the virus altogether for a while, until it returns after a few years.
In either case, Covid-19 will return.
“Should reinfection prove commonplace, and barring a highly effective vaccine delivered to most of the world’s population, SARS-CoV-2 will likely settle into a pattern of endemicity,” the paper concluded.
But when would this even happen?
We’ll likely know whether Covid-19 is endemic by the end of 2021 next year, according to Dr. Julian Tang, a consulting virologist at the Leicester Royal Hospital, and an associate professor at the University of Leicester.
By then, he predicts nearly 80 percent or more of the world will have been infected by Covid-19. In 2022, he expects it’ll become seasonal, like the flu, with coronavirus outbreaks during colder, drier winter months. Influenza and other respiratory viruses usually spread in winters due to weaker immune systems and the environment you spend most of your time in.
In many countries, people get less Vitamin D in winter months, spending more time indoors in crowded spaces. Viruses also live longer in the cold.
Critically enough, all influenza outbreaks have eventually become seasonal after spreading around the world.
Thankfully, vaccines will probably protect you by boosting your immune system when it comes to confronting Covid-19. Some experts suggest that multiple vaccines may be necessary, possibly even on a yearly basis, to stay safe from Covid-19.
Will Covid-19 ever be fully eradicated?
The good news is that completely eliminating a virus is not impossible, even if it is very difficult. For instance, smallpox, a deadly and highly contagious disease which claimed the lives of 3 in 10 people it infected, was eliminated in the 1980s after robust vaccination programs and international coordination.
Dr. Hans Heesterbeek, an expert in epidemiology at Utrecht University, Netherlands, argues that if vaccines are effective in preventing Covid-19, reduce transmission and give long-lasting immunity, then completely stamping out the disease is possible.
“But realistically this is unlikely,” he adds in a caveat. Even for diseases with great vaccines that give you permanent immunity, completely eliminating a virus is incredibly difficult, he notes.
“Endemic disease is therefore the most likely outcome.”