COVID's final game: Scientists know where SARS-CoV-2 will go
This image Hanna Barczyk is available for NPR Hanna Barczyk
In the 1980s, British scientists conducted an experiment that seemed a little unethical at first. Jennie Lavine, a computational biologist, says that volunteers came to the lab and someone squirted virus on their nose.
Researchers created a liquid containing coronavirus particles that they intended to infect 15 volunteers.
Ten people got infected. Lavine says that five of the other infected people were able to fight off the virus. She was speaking at NPR from Karius, a biotechnology company.
After waiting a year, the researchers repeated the experiment. The researchers wondered if getting coronavirus a second time protected people from it again a year later. Or could people be reinfected one year later?
Lavine quickly pointed out that the coronavirus that was injected into the noses of the volunteers wasn't SARS CoV-2, which is the coronavirus responsible for COVID-19. "No. "No. No one got very sick. They probably measured disease severity based on how many tissue boxes were used by each person. All ethical considerations were taken into account when the experiment was conducted.
Researchers were studying a coronavirus called 229E that causes mild colds in humans. The experiment provided some interesting insights into the potential endgame of the COVID-19 epidemic. What's next after this winter's delta surge? Scientists predict that it will. Is the virus coming back next year? The year after?
SARS-CoV-2: Why early hope was there
There was hope that we could put the genie back in the bottle when COVID-19 broke out worldwide. The world could wipe out the virus completely from the population, just as it did with the first SARS coronavirus in 2003.
However, as the virus spread quickly from continent to continent and the number of cases rose, local eradication became the only option. Possibly, some regions could achieve so-called "herd immunity" through vaccinations and exposure. This would allow them to push the virus out of their communities while also keeping it away from others by imposing travel restrictions and immunization requirements.
Lavine states, "It's like OK, if it's not going to be possible to completely eliminate SARS-CoV-2 out of the world," and "then maybe, we would achieve local elimination, like we do with measles, or polio."
Paul Bieniasz, virologist at Rockefeller University, said that the virus must be stable in order to make this possible. The vaccine's protection is long-lasting because it doesn't allow its genetic sequence to change or mutate over time. He says that if you get measles or the vaccine, it will protect you for life. The virus doesn't change much.
However, not all viruses behave in this way. Influenza viruses can mutate very quickly, which can reduce the effectiveness of vaccines. This is one reason you can be reinfected again and again with flu. Kathryn Kistler, a molecular biologist at the University of Washington in Seattle, says that this is why vaccines must be updated every year. "The virus is constantly evolving, and our immune system doesn't recognize it anymore," says Kathryn Kistler, University of Washington molecular biologist.
The rate at which the virus' genetic sequence changes determines whether communities are able to eradicate SARS-CoV-2 locally. The virus looked more like the flu than the measles at the start of the pandemic. The consensus among scientists was that the SARS/CoV-2 virus would not change over time.
Six months after the outbreak, the virus appeared to be on the right track. "To date, there have not been many mutations observed," Peter Thielen, a molecular biologist at Johns Hopkins University, told NPR in June. He spoke to NPR with the headline, "This Coronavirus doesn't change quickly, and that's good news for vaccine makers."
SARS-CoV-2 changed course in December right around the holidays.
South African scientists announced that they had discovered a mutant virus of the virus capable of infecting people again. This would prevent the immune reaction that was caused by an earlier infection. Scientists in the U.K. discovered a fast-growing mutant virus that was about half the transmissible as the original viruses. Another mutant was discovered in Brazil a few weeks later. This caused a second massive surge.
Unexpected change in the course SARS-CoV-2
It was apparent that SARS-CoV-2 was rapidly evolving and was not just mutating. Kistler and her University of Washington colleagues published a new measure to determine how fast SARS-CoV-2 evolves as it adapts to life inside humans. Kistler was stunned when she first discovered the value. She says that SARS-CoV-2's adaptability rate is remarkable right now, about four times greater than for seasonal flu.
The flu is constantly changing so people are at risk each year.
Kistler states that "I don’t believe SARS-CoV-2 is going to stop adapting." It may slow down, however viruses that adapt adaptively tend not to stop evolving. They are not likely to reach the limit of evolution."
Many scientists believe this rapid evolution has enormous implications. This essentially ends all hope of eliminating SARS-CoV-2 from the U.S. and other smaller communities. The coronavirus is likely to be able, just like the flu virus, to infect people again and again. It will return year after year.
"Eventually, everyone will be exposed" says Dr. Abraar Karn, an infectious disease specialist at Stanford University. It's not about whether you are fully vaccinated, or if you aren't.
These findings seem like terrible news on the surface. This sounds like the COVID pandemic, along with physical distancing, quarantining and masks will never end.
Karan does not believe this will be true. He predicts that SARS CoV-2 will continue to circulate in the U.S., but he believes that COVID, the terrible disease we know now, will probably disappear.
Karan states, "When you are fully vaccinated or have been exposed multiple times, you're dealing a very, very different illness and process." You're probably dealing with a disease many of us have had at least dozens of times in our lives.
Coronaviruses have been caught many, many times.
It may surprise you, but the U.S. has managed many large-scale coronavirus epidemics prior to the COVID pandemic.
There are four coronaviruses that are widely circulated, namely NL63, 229E and OC43. These two viruses have been known to infect people for many centuries. The second two have been infected for decades, possibly longer. These are related to SARS-CoV-2, but they are not the same.
Every year, one or more of these coronaviruses infects the U.S. at least one school, daycare center, church, or office and causes illness. Many, many people. These coronaviruses can be so widespread that children in kindergarten are likely to have been infected with at least four.
Rachel Eguia, Virologist at Fred Hutch Research Institute in Seattle, and her colleagues have been studying coronaviruses.
Eguia says, "So we have been studying strains a coronavirus in 1984, 1992 2001, 2008, and 2016". Eguia wanted to know if people can be reinfected once every eight years.
This is the tricky thing about coronaviruses. Just because you have one last year does not mean that you are immune to the same coronavirus infection next year.
The British experiment that was described at the beginning of this article, where virus particles were injected into volunteers' noses twice, is still relevant. The researchers also tested the antibodies of people before they were exposed to the virus again. Although antibodies against the virus did not necessarily prevent people from getting infected again, there was an advantage. Higher antibodies levels were able to prevent people from getting ill and reduce the spread of the virus.
Eguia states that there are a number of studies suggesting that you can get reinfected with coronaviruses every few years. The immunity to seasonal coronaviruses is less than 12 months, according to a Nature Medicine study. They are likely to have caught them at least a dozen times in their lifetime.
They are not noticed by anyone. These coronaviruses are transmitted to us, and our "normal" lives continue. Schools and churches remain open. People congregate in bars and clubs. House parties are continuing. Why? These coronaviruses are usually responsible for colds. These coronaviruses can cause a mild illness, such as a cold, cough, sneezing, and congestion. It is usually milder than the flu, and it resolves in about a week.
Studies have shown that these coronaviruses together cause between 10 and 30% of all common colds in adults. These coronaviruses are a part of modern-day life in many ways. They are part of modern life, and we simply live with them without much fuss.
Could it be the same for SARS-CoV-2 too?
Could SARS-CoV-2 Be a Common Cold?
Scientists are beginning to believe that COVID could eventually become a disease more like these coronaviruses, or a mild flu-like illness.
Karius' Jennie Lavine says, "That's exactly what our computer models predict." She and her colleagues have been combining what is known about four seasonal coronaviruses over the past year to forecast what SARS-CoV-2 would do in the next five, ten, and twenty years. Their findings were published in Science in February.
Two conditions must be met for the new virus to become a mild case of the common cold, she said. First, the immune system must be protected against severe diseases. She says that even if you are infected once or twice, the vaccine should provide long-lasting immunity against severe diseases. It does not have to stop transmission. It must keep you out of hospital.
Rustom Antia at Emory, a colleague of Lavine, said that immunity appears to be holding up so far for at least six months. It's not clear how long this critical immunity will last in people at higher risk of severe diseases.
"We don’t know how the vaccine will perform for people over 60. "We don’t know how many vaccine doses will be required to build immunity, so that if we get infected by nature it is not severe.
However, if natural or vaccine-based immunity is achieved, then the majority of the population will eventually be protected from severe COVID. Only one population would remain vulnerable and exposed: Newborns.
This brings us to the second condition that SARS-CoV-2 must meet to become a seasonal flu: The virus must remain mild in children.
While babies and children can sometimes experience serious complications from COVID, it is generally considered to be low-risk for young children. The reason for the decreased risk is not known. However, a study published in August showed that children's immune systems in their noses are more capable of detecting SARS-Cov-2 faster than those in adults. They can also take steps to prevent it from happening again. According to the authors, the data suggests that children's immune cells in their noses (upper airways) are primed and activated for virus detection.
SARS-CoV-2 remains low-risk for children. However, if a new variant of the virus is not discovered, then children can be infected as soon as they are young. They will also have immunity and protection against severe diseases as adults. In theory, COVID would be a worldwide disease.
The process of building up this immunity can take years or even decades. Antia says that vaccinating everyone against severe diseases is crucial. The sooner people are protected, the quicker COVID can become a less frightening disease.
As with all predictions of viruses, it is possible for this one to be wrong. SARS-CoV-2 has been surprising even the most skeptical scientists over the past year. Paul Bienaisz says that the more information he receives about the immune response to SARS, CoV-2, the more optimistic he is that this endgame scenario, or a variant thereof, will be realized. Based on the evidence we have, it seems like the immune system will eventually prevail over the virus.