Science: Will the outbreak be repeated? The long-term effects of the new coronavirus on humans

The world's growing number of infections, the outbreak control and stability of China continues to have sporadic local cases, the northern hemisphere autumn and winter coming ... Are reminding us that the epidemic prevention pressure is still severe.
From what we know about other viruses, including influenza viruses, rhinoviruses, and other less pathogenic human coronaviruses, many respiratory viruses can repeatedly infect humans, which is one of the potential reasons why these viruses can exist in human society for a long time.
, there have been reports of second cases of new coronavirus infection.
world health organization has also pointed out that the impact of the new crown outbreak will continue for decades.
, will the new crown come back again and again, or will it become popular in some areas for a long time to coexist with humans? Recently, Science, a leading academic journal, published opinion papers from two public health experts at Columbia University, Dr. Jeffrey Shaman and Dr. Marta Galanti, exploring the four determinants of the long-term effects of the new coronavirus on humans.
Screenshot Source: Science The duration of human immunity usually occurs when the body is first infected with the virus, the body forms an accessible immunity, T cells can kill cells infected by pathogens, and B cells can produce antibodies to specific neutralized antigens.
T and B cells also develop into memory cells that can be rapidly activated and multiplyed and act when secondary infections are caused by the same pathogen.
, however, this process is affected by a number of factors, including inadequate access to immune response, weakened immunity and immune escape, which increase the risk of secondary infection.
As far as the first two points are concerned, although existing studies have shown that new coronavirus infections can induce the body to produce antibodies regardless of their severity, levels of antibodies in different bodies are not consistent, and there is no clear answer as to whether these antibodies are persistent and provide long-term effective protection.
immune escape, the virus accumulates mutations in the process of infecting the host population, which may lead to changes in the protein structure of the virus surface, which in turn affects the effects of antibodies previously formed by the body.
has so far been observed that the new coronavirus's genome mutation is not very fast, is one-in-two of the coronavirus that causes the common cold, is a quarter of the HIV virus, and is slower than the flu.
, however, there have also been recent reports of potential "drug-resistant" gene mutations in the new coronavirus, prompting increased monitoring of the molecular evolution of the new coronavirus to provide information for neutral antibodies and the development of new coronavirus vaccines.
experts point out that very few cases of secondary infection are currently sufficient to indicate the degree and duration of the body's immunity to the new coronavirus at the population level.
information from four other common people with coronavirus (OC43, HKU1, 229E and NL63) suggests that repeated infections of the same human coronavirus within one year are common and that continuous infections of the same influenza strain can occur in less than 2 years.
, on the other hand, more pathogenic viruses may maintain their immunity for longer because they cause a stronger immune response.
if re-infection of the new coronavirus proves to be widespread, "unless an efficient vaccine is available to the majority of the world's population, the new coronavirus infection is likely to become a regional epidemic".
characteristics of the new coronavirus are most common respiratory viruses in the tropics except in the tropics.
this is related to the adaptation of viruses to changes in environmental conditions, human behavior, or immune function.
, for example, in temperage areas, winter flu rates are highest, influenza viruses are more stable in dry environments, indoor gathering in winter is also more conducive to transmission, and short periods of sun may inhibit the body's immune function.
, the four pathogenic common human coronavirus also showed seasonality in temperative regions.
the impact of seasonal environmental conditions on the viability and transmission of the new coronavirus has not yet been determined.
Some studies suggest that, although not enough to stop the first pandemic, light and humidity may have an impact on the new coronavirus, which may develop into seasonal transmission as some populations become more immune to the new coronavirus and the vaccine becomes more effective.
image source: 123RF different viruses interact with the simultaneous epidemic of respiratory viruses may also be "competing for resources", mutual interference.
many studies have shown that the protective effects of the body can cause negative interference with other viruses within a short period of time after the first infection.
mechanism is that the interferon reaction in the host body increases after the first infection, which in turn inhibits subsequent other infections.
even if the effect is short-lived in the individual, it can have a powerful effect on population size, reducing the prevalence of a virus.
at the population level, there are also studies suggesting that the prevalence of different viruses in the same region will be "overdred."
, for example, during the H1N1 influenza pandemic, there was no expected surge in flu cases in the autumn of the European common cold epidemic.
study, published recently in The Lancet-Microbiology by a team at Yale University School of Medicine, also suggests that rhinoviruses, which cause the common cold, can prevent influenza virus infection by activating the body's antiviral defenses.
image source: 123RF Although some cases of simultaneous infection with new coronavirus and other viruses (such as influenza, respiratory syncytial virus) have been recorded, there is a lack of large-scale detection of co-infection data.
In addition, modelling studies have shown that if the new coronavirus and other β-coronavirus (OC43 and HKU1) cause similar immune duration (about 40 weeks), then the new coronavirus may erupt every year, and if the population's immunity to the new coronavirus lasts longer, then with some protective cross-immunity from other β coronavirus, the effects of the new coronavirus may gradually diminish and re-epidemic years later.
, of course, there are many factors involved, and there are many unknown potential circumstances.
how the new coronavirus interacts with other respiratory viruses at the population level still needs future long-term surveillance data to answer.
public health interventions although many of the above-mentioned problems have yet to be accumulated by scientific evidence to arrive at a clearer answer, but different respiratory virus transmission methods are similar, prevention and control measures are common.
wearing personal protective equipment such as masks, increasing social distances, reducing indoor aggregation, and enhancing hygiene can all reduce the spread of new coronavirus and help reduce the pressure of seasonal influenza outbreaks.
: 123RF in the southern hemisphere, a significant reduction in winter flu may be related to the implementation of these public health interventions and potential viral interactions.
, influenza and new crown outbreaks pose a serious threat to the public health system.
, these measures are not difficult for us to do.