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“The more answers we find, the more new questions emerge,” said Seema Lakdawala, professor of microbiology and molecular genetics at the University of Pittsburgh.
What she is talking about here is the dilemma that scientists have faced in order to decipher the new coronavirus (SARS-CoV-2) epidemic since the new coronavirus disease first appeared and began to spread globally in December 2019.
Now that two years have passed, researchers have made tremendous progress in understanding the new coronavirus, developing a new coronavirus vaccine and a treatment to combat the new crown disease.
However, as experts say, the more you know, the less you will find, and there are still some basic problems that remain unsolved.
Experts say solving these mysteries could help further strengthen the fight against the coronavirus.
Here are three key questions about the coronavirus that remain unanswered.
1. The exact origin of the virus
“The source of the initial outbreak has not been identified,” Britain’s Health Security Agency, which oversees infectious disease control, said on its website.
In February 2021, the World Health Organization sent a team of experts to China to investigate the origin of the new coronavirus. The findings indicated that the new coronavirus was “very likely” transmitted from bats to humans through another intermediate animal host, but more research is needed. to determine the exact origin.
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WHO Director-General Tedros Adhanom Ghebreyesus said the investigation was hampered by a lack of data and transparency in China.
The WHO findings also said it was “extremely unlikely” that the virus was transmitted to humans from a laboratory leak.
However, Tedros said after the report was released that the investigation was not comprehensive enough. More data and research are needed to draw stronger conclusions.
Tedros also published an opinion piece in the journal Science in October, saying, “Until sufficient evidence is available, the laboratory leak cannot be ruled out.”
That same month, WHO established the Scientific Advisory Group on the Origin of Novel Pathogens (SAGO) to investigate whether the virus spread to humans from animals at the Huanan Seafood Market in Wuhan, or was the result of a laboratory leak.
The advisory group will hold its first meeting in November 2021.
Tedros said the findings by the expert scientific advisory group could help shape future policies to reduce the likelihood of animal viruses spreading to humans.
In October 2021, U.S. intelligence agencies declassified reports that the exact origin of the new coronavirus may never be found.
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WHO Director-General Tedros Adhanom Ghebreyesus
The declassified document also said that it can be determined that the new coronavirus is not an artificially developed biochemical weapon, and that animal transmission to humans and laboratory leakage are the two most likely hypotheses.
However, the declassified documents also said that there is not enough information to determine which of the two possibilities is the final conclusion.
China’s backlash against the new coronavirus is the result of a lab leak.
In November 2021, John P. Moore, a professor of microbiology and immunology at Cornell University in the United States, published an article on the U.S. health news website “Stat News” saying, “We may never know exactly what the new coronavirus is. origin.”
Moore said that there are many other “weird” theories about the origin of the virus, which are basically untenable, and the main discussions today are natural transmission and laboratory leaks.
2. The amount of virus infection
The viral load refers to the amount of virus required to cause an infection.
For the new coronavirus, the viral infection volume is not clear, that is, we do not know how many virus particles a person needs to inhale to become infected.
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The Centers for Disease Control and Prevention (CDC) said, “It is not known how much virus infection is required for the new coronavirus to cause infection.”
The CDC also said that animal studies and epidemiological investigations have shown that inhalation of the virus can cause infection, but the infection caused by inhalation of the virus or virus contact with mucous membranes (such as the eyes) “is impossible and difficult to quantify.”
“Without human trials, it is difficult to determine the amount of viral infection of the new coronavirus in humans,” said Laca Davala, a professor of microbiology and molecular genetics at the University of Pittsburgh.
For example, the average influenza requires only 10 virions to infect, while Middle East respiratory syndrome (MERS) requires thousands of virions to infect.
But with the new coronavirus, the amount of virus needed to reach infection has not yet been determined.
The closest they know is data on 229e, a type of coronavirus that causes the common cold, Lakadawara said, with a virus similar to the flu.
“But we don’t know if the new coronaviruses are the same,” he said. “In the case of the Omicron variant, it’s not clear if it’s more contagious because the virus has a lower infection rate.”
“We don’t know if it takes 100 virions, 1,000, or 10,000 virions to cause an infection.”
Experts say there is no doubt that the new coronavirus is highly contagious, but it is not clear whether this is because the infection rate of the virus is low (only a small amount of virus is needed to cause an infection), or the infected person releases a large amount of virus in the environment.
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Much of the current information on the potential contagion of a COVID-19 patient, and how long a patient must be quarantined, is based on how long the patient has released the virus.
Lakadawala said that if the virus infection level can be determined, it will be possible to better assess the risk and determine the probability of infection of people in restaurants, schools and other places. “Right now we can only be careful to avoid the spread of the virus, but many measures can be improved if the amount of virus infection is known.”
But if the factor of vaccination is taken into account, although the amount of virus infection is not clear, after people are vaccinated, more virus should be needed to cause infection.
“After you get vaccinated, you need to inhale more virus to get infected,” Lakadawala said.
Several studies are currently under development, and if conducted, volunteers will be exposed to varying amounts of the virus in a controlled environment to gain more information about viral infection levels.
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Vaccination maintains protection against Covid-19
3. The amount of antibodies needed to prevent infection
It’s unclear how many antibodies a person needs to have in order to protect against the new coronavirus.
This is called the “Correlates of Protection” and can be used to assess how well the body is protected from disease or infection.
Some experts agree that how many antibodies are needed in the body to be protective is key information in fighting the new coronavirus disease.
“Vaccines against the new coronavirus urgently need to know the protective association value,” Florian Krammer, professor of microbiology at the Icahn School of Medicine at Mount Sinai, wrote in Science in July 2021. road.
In the article, Kramer illustrates the importance of knowing the number of antibodies with a protective association value, which allows us to know the minimum number of antibodies required to be protective.
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When the new coronavirus enters the body, the Y antibody attacks the virus
One reason is that if we know the minimum number of antibodies needed to be protective, new vaccines can be developed and approved more quickly, without the need for lengthy Phase 3 trials.
Knowing the protective association value could also allow immunocompromised people to be vaccinated more efficiently, and booster doses can be given if they are found not to be producing sufficient numbers of antibodies.
In addition, determining the protective association value can also tell health authorities what percentage of the population has enough antibodies to protect against infection.
But Cramer said there was no way to determine a protective association that would apply to all vaccines, all mutated viruses and all people, but it would still be very useful in the fight against Covid-19.
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Experts say wearing masks is necessary for epidemic prevention
Lakadawala said that in the case of the Omicron variant, the number of antibodies produced by existing vaccines is relatively low.
“But that doesn’t mean we don’t have protection, and existing data continue to show that getting vaccinated protects us from severe disease compared to not getting vaccinated.”
Experts also say that the emergence of new mutant strains can lead to changes in viral infection and protective association values.
“Every time the virus spreads, the possibility of mutation increases, and each mutation of the virus will affect the above variables. Therefore, it is necessary to avoid continuous infection of the epidemic as much as possible.”
In order to reduce the spread of the virus, while researchers try to answer questions, everyone must continue to take preventive measures: wear a mask, get vaccinated, and maintain social distancing.