On Sunday (Feb. 7), two new studies brought bad news about the Newcastle pneumonia outbreak. In South Africa, one study showed that the AstraZeneca vaccine offered “minimal protection” against the South African variant of the virus. Another study found that the British variant of the virus, which has proven to be more infectious and potentially more deadly, is “rapidly becoming the dominant strain” in the United States.
What does this mean for the future of the Epidemic if humans are unable to outcompete the changing virus and the new strain becomes endemic?
There are two ways to end the epidemic: one is to achieve herd immunity in all countries and let the virus die out; the other is that countries may learn to control the spread of the virus, but not eliminate it completely. The latter is what virologists call an “endemic virus” (or “endemic disease”), and many believe this is the most likely outcome.
What exactly is “endemic disease”?
An endemic virus is a virus that is already prevalent in human populations in many parts of the world: it is neither too virulent nor too weak, and it does not spread as quickly as during an epidemic, but it does not disappear either. Influenza, measles, malaria, AIDS, Zika, etc. are all endemic infections. And there is no biological reason why a novel coronavirus cannot also become endemic – there are already four coronaviruses circulating globally as endemics.
Whether a virus becomes endemic or not depends ultimately on the biology of the virus and the human immune response.
As the virus spreads, random mutations occur. These mutations often have no effect on the virus, but they sometimes change the way the virus infects the host, making it more viable in the long term. For example, mutations can affect the lethality, infectiousness, or asymptomatic phase of an infection, thus making the virus more likely to survive.
The human immune system also has a role to play in making a virus endemic to the terroir. As a virus and its vaccine spread separately around the world, more and more people will become immune. In some cases, our bodies produce this immunity causing the average symptoms of that disease to become less frequent or more mild.
As long as just the right balance is maintained between infectiousness and immune protection, a virus can become endemic: it will infect the population at about the same rate as it disappears, and the infection rate will reach a relatively stable level. In other words, when the “effective reproduction rate” of a virus is equal to one, that is, each infected person will transmit the disease to no more or less than one other person on average, keeping the number of infected people approximately constant.
Some studies have shown that this can happen with coronaviruses. Based on data suggesting that immunity to neo-coronavirus does not prevent a person from re-infection, but does prevent the severe symptoms of re-infection, a recent study further suggests that as more people are exposed to neo-coronavirus in childhood, they may retain protection throughout their lives so that neo-coronavirus becomes much like the common cold.
This process is nothing new: Many societies throughout history have witnessed pandemics becoming endemic.
Historians have long noted recurring outbreaks of infectious diseases, most likely smallpox and measles, during the Eastern Han period. Between 151 and 185 AD, these viruses caused seven outbreaks and likely became endemic in some areas of China. In 208, when Cao Cao’s forces were defeated at the Battle of Red Cliff, historians-according to the Three Kingdoms, this was Cao Cao himself- -noted the major role that disease played in this battle. Smallpox as a terroir disease in southern China would explain this: while the southern army facing Cao Cao was largely immune to the infection, the disease became rampant among Cao Cao’s northern army and led to a setback for the numerically superior Cao army.
According to Cao Cao, the key to success or failure in the Battle of Chibi should have been the massive epidemic, not the matter of whether to launch a fire attack.
Humans have been dealing with endemic diseases for centuries, and scientists are increasingly inclined to believe that the New Coronavirus is likely to become an endemic disease.
Will Neocoronavirus become endemic?
Currently, most attention is focused on “eradicating” the virus, and many people are waiting for the number of cases to drop to zero each day so that Life can return to normal. However, this may not be realistic. Many scientists believe that we should plan for the epidemic to become endemic and learn to live with the virus.
At a Jan. 25 World health Organization (WHO) news conference, Mike Ryan, executive director of the WHO Emergency Program, warned, “Remember, we have only eradicated one disease from the planet: smallpox. And we’re fighting polio, and we’re trying to eradicate measles.”
It’s true: eradicating viruses is very difficult, even for diseases for which people have almost perfect vaccines and permanent immunity. And in the case of the new coronavirus, current vaccine and immunology studies suggest that we are far from either.
As recent studies by South African scientists have shown, new variants of the virus may reduce the effectiveness of some vaccines. And even if our vaccine works perfectly, manufacturing and logistical constraints will result in a vaccine that still won’t take care of most developing countries in the future. Most vaccine supply projections show that most people in these countries will not be vaccinated until early 2022.
As a result, there will be plenty of room for the new coronavirus to continue to spread and mutate, further increasing the likelihood that it will become an endemic disease. Therefore, according to Ryan, the “standard of success” should not be to eliminate or eradicate the virus, but to “reduce its lethality and its ability to hospitalize people and disrupt our economic and social life.
This means that measures such as social distancing, masking, and regular testing should not be seen as temporary solutions, but perhaps as long-term adaptation measures. If the new coronavirus becomes endemic, these measures will not necessarily disappear, but may be integrated into daily life, promoting new habits and new ways of doing business, such as high-quality air ventilation and monitoring, automated work, diagnostic kits, and new treatments.
In this case, vaccination will continue to be a priority, but in a different way. The goal of vaccines will not be to try to eradicate the virus, but to minimize the transmission rate of the terroir disease and to try to stop the negative effects of new mutations.
If not handled properly, mutations can lead to occasional outbreaks, so monitoring for new mutations is critical to a long-term vaccination program. Recent concerns surrounding Variant viruses in the United Kingdom, Brazil and South Africa have made many scientists and public health officials aware of this. on Feb. 5, the U.S. Food and Drug Administration (FDA) said it will propose guidelines on how manufacturers of new coronavirus vaccines, therapeutic agents and diagnostic tests should respond to new virus variants. guidelines.
Ultimately, it is possible that public health agencies will have to establish a global surveillance network of laboratories and scientists, similar to that used to study influenza variants, to update vaccines on a regular basis.
Endemic new coronaviruses: Is the future bright or dark?
Some scientists warn that the impact of the new coronavirus becoming endemic remains unclear. It is possible that it will become less virulent and easier to manage, but this may not necessarily be the case.
Angela Rasmussen, a virologist at Georgetown University’s Center for Global Health Science and Security, told the Wall Street Journal. “People seem to think that when a virus becomes endemic, it will wane and not be as severe. This misconception stems from the fact that usually viruses evolve to maximize the number of infections before they kill (the host).”
Although this idea was popularized by the “law of declining virulence” developed by American virologist Theobald Smith in the early 20th century, scientists today agree that there is no direct evidence that There is no direct evidence that viruses mutate over Time, causing them to gradually lose their virulence.
Rasmussen argues that in the case of neocrown pneumonia, because of the considerable time between infection and the onset of symptoms, “there is not much pressure for the virus to become more attenuated because it is already spreading and finding new hosts and new opportunities for replication before the host becomes ill.”
This means that even if it becomes endemic, the infection rate of the new coronavirus may still be quite high. Whether this will plunge the health system into crisis and continue to claim many lives will depend on other major factors, such as how long human immunity to the virus is retained, how quickly the virus mutates, and how widespread the immunity of the aging population is during the epidemic.
This will also put a lot of pressure on developing appropriate medical solutions. If scientists can significantly reduce the worst effects of the virus through vaccines and treatments, then perhaps new coronavirus infections will become like other controllable endemic diseases. However, this may require cumbersome measures, such as annual vaccination against Neoplasma pneumonia, as is the case with influenza.
In any case, this transition from an epidemic to a stable endemic infection will not occur overnight. Depending on the different factors described above, the world may face several years of difficult post-epidemic transitions: sustained mutations, localized outbreaks, and continuous vaccination campaigns.
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