Latest Coronavirus News
Want to know how the novel coronavirus will be impacting humanity in five years? So do scientists.
This week researchers reported their COVID-19 projections for the next five years in the journal Science. They considered a wide variety of factors, like future vaccine effectiveness and vaccine hesitancy, how soon people may be re-infected, and how the weather could influence the virus that causes COVID-19.
The researchers also looked at possible interventions like closures, movement restrictions, and lockdowns. Some of their conclusions highlight the importance of learning the details of human immunity to COVID-19 as soon as possible.
As the world clamors for answers to the biggest health crisis in generations, these future scenarios show that steps we take now could lead to a virus with seasonal peaks, or a virus that steadily spreads all year.
“Much of the discussion so far related to the future trajectory of COVID-19 has rightly been focused on the effects of seasonality and non-pharmaceutical interventions [NPIs], such as mask-wearing and physical distancing,” said Princeton professor and co-first author Chadi Saad-Roy in a statement. “In the short term, and during the pandemic phase, NPIs are the key determinant of case burdens. However, the role of immunity will become increasingly important as we look into the future.”
How Much Does the Weather Affect COVID-19 Transmission?
Now that temperatures are cooling down for fall, many are asking how this could influence the novel coronavirus. The world has now seen that hot temperatures do not always slow the spread of COVID-19. Yet this study predicts warm weather will protect against the novel coronavirus in the future.
This study finds agreement with past research, noting that seasons do influence the rate of COVID-19 infection, but that the influence is small, especially now while so many people are vulnerable to infection.
Over time, as more people are either infected or vaccinated, these researchers predict that season changes will matter more to the way the virus spreads. That's because more people in the population will be immune, leaving others more vulnerable during temperature variations.
In other words, with so many potential hosts, the virus barely slows down in the summer now. But when more people are eventually immune, it will probably take on a seasonal nature.
Many scientists predict that eventually SARS-CoV-2 will be most active in winter months, as are other known coronaviruses that infect humans. The question is: how soon?
What Are the Consequences of COVID-19 Protective Measures?
The study looked at different scenarios using different time lengths of restrictions like school and business closures.
The researchers saw a relationship between primary infections and protective measures like business closures, mask-wearing, and social distancing. Primary infections refer to the first time someone is infected by a virus.
Specifically, the study finds that the longer restrictions are kept in place, the fewer people are likely to develop a primary infection.
On the other hand, these restrictions also increase the number of people who are re-infected with so-called "secondary infections," this study projects. Secondary infections are any re-infections following the first infection.
Yet if people are artificially protected against primary infections longer, a peak of secondary infections will also last longer.
This demonstrates some of the thorny issues policymakers must consider while planning for the virus, and some of the many confounding variables that must be considered in future projections.
Will the Coronavirus Vaccine Work?
Labs the world over are working ferociously to produce a safe and effective COVID-19 vaccine. None have been released to the wider public yet. What could a future vaccine mean over the next five years?
Many people around the world rest their hopes on a COVID-19 vaccine to bring public life back to normal again. The researchers caution that immunity can be imperfect, though.
They ran models according to different hypothetical strengths of immunity, both acquired after an infection and received from a vaccine.
They also had to consider another hypothetical: What if some people are more vulnerable to infection following their first infection? This can happen following dengue fever infections, for instance, in a phenomenon called ADE (antibody-dependent enhancement).
Your antibodies normally fight off infections, but in the event of ADE your antibodies aid the virus and help it to replicate itself. SARS-CoV 2 hasn’t shown this behavior, but virologists have documented it in other coronaviruses that infect humans.
Potential Changes in the Future
The world's knowledge about SARS-CoV 2 has changed over time on topics ranging from nonsymptomatic carriers to aerosol spread. Experts have yet to settle many similar controversies. In many ways, these projections highlight how much remains unknown about the next five years.
“Ultimately, we don’t know what the strength or duration of natural immunity to SARS-CoV-2 -- or a potential vaccine -- will look like,” said study author Caroline Wagner, an assistant professor of bioengineering at McGill University. “For instance, if reinfection is possible, what does a person’s immune response to their previous infection do? Is that immune response capable of stopping you from transmitting the infection to others? These will all impact the dynamics of future outbreaks.”
We don't know how long primary immunity to COVID-19 lasts. And if it eventually wears out, we don't know whether these people are more vulnerable to another infection.
And we don't know precisely what steps governments will take to control the virus. There are costs and benefits to different approaches, complicating the matter. But the researchers found that more limited prevention scenarios were more likely to lead to steady, yearlong infection rates for years to come.
We also don't know how effective a potential vaccine will be. Will it be nearly 100% effective like the polio vaccine? Or will it be more like the flu vaccine, which in recent years has ranged from 10% to 60% effectiveness? Most scientists expect a modest protection rate.
Answering these and other questions is crucial to fill gaps in our understanding, gaps that could prove deadly as coronavirus continues to cut its way through humanity.