Roughly one year has passed since the coronavirus pandemic began sweeping the globe, infecting well over 81 million people worldwide and killing more than 1.7 million. COVID-19, the disease caused by infection with the coronavirus, has disrupted daily life in a profound way, leaving virtually no one unaffected.
Restrictions have been put in place around the world in an attempt to mitigate the spread of the virus, mandating drastic changes in daily routines for billions of people. Scientists launched thousands of research projects to understand the virus, and governments rushed to subsidize the development, production and distribution of vaccines for COVID-19, offering hope that the end of the pandemic could be within sight. And yet, for all that has changed and all that we have learned about COVID-19, there remain many unanswered questions.
Here are some of the things we still don’t know about COVID-19.
Where did the virus come from?
Though the coronavirus pandemic has been traced back to the live-animal market in Wuhan, China, it is unclear how a virus that is believed to have originated in bats jumped to people. The World Health Organization will center its own investigation into how the virus became infectious to humans in Wuhan, yet it remains unclear how much the government of China, which attempted to hide the outbreak in its initial weeks, will cooperate. The WHO will look at the different animals sold at the market and dig into hospital records of those first infected with the virus to try to determine if a specific species transmitted it.
“Finding an animal with a SARS-CoV2 infection is like looking for a needle in the world’s largest haystack. They may never find a ‘smoking bat,’” Columbia University virologist Angela Rasmussen told the journal Nature.
Why are children less at risk than adults?
According to data compiled by the Centers for Disease Control and Prevention, children below the age of 18 have been infected, sickened and died from COVID-19 at significantly lower rates than adults. While that age demographic accounts for 22.6 percent of the U.S. population, in the early stages of the pandemic they accounted for just 3 percent of COVID-19 cases. In the months since then, the percentage has risen to between 12 percent and 15.9 percent, according to a study by the American Academy of Pediatrics and the Children’s Hospital Association. Hospitalization and death rates from COVID-19 remain lower than those for adults.
The underlying reason for the discrepancy between children and adults is still being researched. A study published in Nature suggests that kids’ immune systems are better able to handle the virus and that some children may develop antibodies for the virus without ever testing positive for it.
With research still ongoing, the CDC is quick to warn that it isn’t safe to assume that children aren’t contributing to the pandemic.
“While fewer children have been sick with COVID-19 compared to adults, children can be infected with the virus that causes COVID-19, can get sick from COVID-19 and can spread the virus that causes COVID-19 to others,” the CDC states on its website.
What is the herd immunity threshold?
Herd immunity describes the point at which an epidemic stops spreading because enough people are resistant to a disease — either because they contracted and survived it or through vaccination — that the infectious agent cannot find enough new hosts to infect, protecting the entire population. As Dr. Anthony Fauci points out, herd immunity for COVID-19 is, so far, based on guesswork.
After being criticized for comments he made to the New York Times about what the herd immunity threshold for the COVID-19 vaccine may be, Fauci admitted to CNN that scientists don’t yet have a specific answer.
“We have to realize that we have to be humble and realize we don’t know. These are pure estimates and the calculations that I made — 70, 75 percent — it’s a range. The range is going to be between 70 and 85 percent,” Fauci said.
He drew a comparison to measles, for which the herd immunity threshold is 90 percent. Because measles is more transmissible than the coronavirus, Fauci said he estimates the necessary level of immunity for COVID-19 will be lower. As of Tuesday, just 2 million Americans out of a population of over 330 million had received the vaccine.
What are the long-term health implications?
President Trump’s swift recovery from COVID-19 after a brief hospital stay led many people to underestimate the dangers of the disease. Growing research suggests that while most patients recover from the disease within weeks after contracting it — and less than 2 percent of cases in the U.S. are fatal — a significant number face longer-term issues. According to the CDC, the most commonly reported long-term symptoms include fatigue, shortness of breath, cough and joint and chest pain. Other patients have reported depression, difficulty concentrating, muscle pain, intermittent fever and lasting headaches. Less common long-term side effects include inflammation of the heart muscle, lung abnormalities, renal problems and hair loss. A study conducted by Ohio State University found that 30 percent of two dozen athletes at the school who tested positive for the virus suffered cellular heart damage and 15 percent showed signs of myocarditis, or heart inflammation. A small number of COVID-19 patients developed psychosis, apparently resulting from biochemical changes in the brain brought on by the virus. How long these side effects may last, or why they impact some patients and not others, is not yet known.
Are the vaccines safe and effective for children under the age of 16?
While the Pfizer and Moderna vaccines now being given to Americans have been approved for use in people over the age of 16, research is still being conducted to determine whether they are safe for younger children. In part, that’s because children were not included in the initial vaccine trials, Dr. Roberta DeBiasi, head of pediatric infectious diseases at Children’s National Hospital, told NPR. “So for the Pfizer product, they did include down to 16 years of age in that initial set of data that we saw,” DeBiasi said, “And in fact, they had been enrolling children down to 12 years of age since October. And there were even, you know, a couple hundred children for which we had a little bit of preliminary data to look at for that product. For the Moderna product, they are now just launching a 12- to 17-year-old group of individuals to be studied, and they’ll have over 3,000 children in that study as well.”
DBiasi said that the results of the studies should be available by January or February.
How long will immunity last after vaccination?
After being vaccinated, the body generally takes a few weeks to build immunity to an infectious disease. According to the CDC, that means a person who receives a vaccine can still be infected with COVID-19 and infect others during that period. What’s less known, however, is how long immunity will last once a person builds it following vaccination. One study published in the New England Journal of Medicine showed that antibodies for the virus remained in the body three months following the second dose of the vaccine, but more research is needed.
Will people need to be vaccinated every year?
Viruses, whether the flu or COVID-19, mutate constantly. As with the latest, possibly more contagious strain of COVID-19 that was first identified in the United Kington and has since spread to several countries, mutations can be worrisome, but not all of them will require the production of a new vaccine. The common flu mutates so rapidly that new immunizations are required every year. As yet, it remains unknown whether COVID-19 will be eradicated through vaccines currently in the pipeline or whether it will mutate fast enough to require that people get a yearly immunization for it.
After being vaccinated, can a person still spread COVID-19?
While the COVID-19 vaccines offer the best hope for returning to normal, prepandemic life, health experts are quick to warn that even after being inoculated, social distancing measures like face masks may still be needed until a large enough percentage of the population also receives one. “We know vaccination will prevent you from getting sick, but we do not know if the vaccine will prevent you from spreading the virus to others yet,” the University of Washington says on its website.
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