How does the novel coronavirus mediated transmission need more relevant evidence research.
For now, strong public governance is more effective than relying on the virus to self-degrade.
Summer is approaching in the northern hemisphere.
One question remains: will the advent of high temperatures help reduce the novel Coronavirus (SARS-COV-2) epidemic?
Other members of the same family as novel Coronavirus, such as SARS, most of them show a certain seasonal pattern — in the summer of high temperature and humidity, the virus activity will decrease.
SARS slipped out just before the summer.
But now there is bad news.
On 18 May 2020, researchers at Princeton University published a research paper in the prestigious journal Science, saying that it is already summer in the northern hemisphere, but rising temperatures are unlikely to significantly curb the spread of COVID-19.
The researchers note that it is still not clear whether seasonal climate and geographic changes will significantly alter the trajectory of the coVID-19 pandemic, given the presence of highly vulnerable populations in the community.
The world is still in the midst of a coVID-19 pandemic.
In this case, virus transmission generally does not follow the usual pattern.
Novel Coronavirus is now circulating in the community and there is still a large number of susceptible people, so it is more powerful public health measures that can contain viruses.
More evidence is needed on how the novel Coronavirus epidemic will play out, so no one can really tell whether the virus will make a comeback in the fall.
Shu Yuelong, Director of the National Influenza Center and President of the School of Public Health at Sun Yat-sen University (Shenzhen), told Caijing that the possibility of a novel Coronavirus with similar seasonal transmission could not be ruled out, but more research is needed.
It will take at least a year or two to get a better view.
Virus and temperature
It is commonly believed that coronavirus is incompatible with high temperature and is more sensitive to heat.
A study published in the Lancet Microbiology on 1 May showed that a novel Coronavirus was very stable at 4°C, and that a coronavirus became inactive 5 minutes later as the ambient temperature rose to 70°C.
Coronavirus has a complex structure. Its outer layer is covered by an envelope, which is dotted with prominent rod-shaped protruding proteins, so it looks like a medieval European imperial crown, hence the name “coronavirus”.
Envelopment not only maintains the structural integrity of the virus, but also participates in the invasion of the host cell, helping the virus recognize and bind to receptors located on the host cell membrane.
Once the envelope binds to the cell membrane of the host cell, the core of the virus — the DNA, RNA and protein that reside inside the virus — enters the host cell, and the infection is complete.
This envelope allows the virus to better adapt to cooler conditions.
In colder conditions, the outer envelope hardens into a rubbery form, just as the fat in cooked meat hardens as it cools, protecting it from the virus for longer.
But at higher temperatures, the protection against the virus is reduced.
As a result, most enveloped viruses tend to exhibit strong seasonality.
SARS coronavirus (SARS-COV) can survive for four days at 37℃.
56℃ heating for 90 minutes, 75℃ heating for 30 minutes, can make the virus inactive.
Another coronavirus, HCOV-229E, loses infectivity at 56 ° C for 10 minutes, or 37 ° C for several hours.
High temperatures in summer are often accompanied by intense ultraviolet light.
Ultraviolet light breaks down the nucleic acid, which destroys the virus’s genetic material, making it unable to continue replicating and rapidly depleting.
This effective method of killing bacteria and viruses, common in hospitals, disinfects all kinds of equipment.
Back to the novel Coronavirus, if the high temperature can prevent virus replication infection, then the novel Coronavirus transmission should break out in different periods around the world at this time.
The reality is not so good.
Novel Coronavirus transmission continues even as summer begins in the Northern Hemisphere.
On May 27, there were more than 8000 new novel Coronavirus infections in Russia, with a total of over 370,000 cases.
Earlier, Researchers at Harvard Medical School analyzed the spread of the virus in Asia.
It turns out that the novel Coronavirus that sparked the pandemic is not as sensitive to weather as many expected.
The Harvard researchers concluded that the increase in cases in China’s cold and dry provinces of Jilin and Heilongjiang was similar to that in tropical regions such as Guangxi;
Temperature and humidity changes in spring and summer do not have a significant impact on COVID-19 growth.
Novel Coronavirus with temperature
With the northern and southern hemispheres, the seasons change.
Researchers are trying to discover through more studies the relationship between novel Coronavirus and climate.
If novel Coronavirus resembles a typical flu virus, its transmission may worsen with the season and ease with the northern hemisphere, Marc Lipsitch, an epidemiologist at Harvard University, said in an interview with the media.
In a paper published on 20 April on medRxiv, a preprint platform of the medical journal, researchers from Italy showed that the novel Coronavirus’s rate of spread peaked in temperate regions of the Northern Hemisphere with an average temperature of around 5℃ and a moisture content of 4-6 g/m3, while it was lower in warmer/humid and cooler/drier regions.
This suggests that environmental factors, including seasonal climate change, can strongly influence the spatiotemporal patterns of infectious disease outbreaks.
But this does not address the relationship between the coVID-19 global epidemic and climate, or whether climate can contain the epidemic.
On 6 May, researchers from the London School of Hygiene and Tropical Medicine (LSHTM), writing in the Medical journal Lancet Planet Health, noted that the worldwide spread of irus from a novel Coronavirus shows that season cannot be considered as a key regulator of irus transmission from a novel Coronavirus.
Although climate warming may slightly reduce viral transmission, there is no evidence that climate warming will reduce the effectiveness of novel Coronavirus transmission to such an extent that additional interventions to curb viral transmission are hardly required.
To better understand novel Coronavirus, scientists are studying novel coronaviruses similar to others, such as SARS and MERS.
Novel Coronavirus shares nearly 90% of ITS DNA.
The SARS outbreak began in November 2002 and lasted until July of the following year.
In between, the spread of THE SARS virus was quickly curbed by a range of public health measures, making it hard to tell whether early intervention was at work or whether the virus showed a natural decline as the weather warmed.
Another brother of Novel Coronavirus, the MERS virus, began in September 2012 in Saudi Arabia, where temperatures were generally high.
Unlike SARS, it has never been completely contained and new cases have cropped up sporadically so far.
Even if novel Coronavirus has some correlation with temperature, summer is no longer the key factor in the current global COVID-19 pandemic.
Warmer summer temperatures in the northern hemisphere are unlikely to significantly curb the spread of COVID-19, according to a study by Princeton University researchers on May 18.
While climate may play a role in regulating the size and timing of novel Coronavirus outbreaks within a specific location, the presence of a large number of susceptible individuals remains a more fundamental driver of epidemic onset.
China experienced the first wave of COVID-19 at the beginning of 2020. The epidemic war quickly cut off local transmission, and the infection rate among the population was low.
Yang Weizhong of the Chinese Preventive Medicine Association has written that once a new source of infection is not contained in time, it is easy to spread among people and cause a rebound of the epidemic.
This means that it remains to be seen whether the coming of summer will somehow curb the viral epidemic of novel Coronavirus.
The London School of Hygiene and Tropical Medicine researchers believe that further research into the impact of climate change, air pollution and other external factors on COVID-19 transmission needs to consider migration from areas with high incidence of coVID-19, population susceptibility and surveillance for respiratory infections.
Policy makers must now focus on reducing human contact within communities, and any coVID-19 risk projections based on climate information should be interpreted with caution.
Michael Ryan, WHO’s head of emergency programmes, also pointed out that there has been no second wave of the disease, but the first wave is now under way, and according to data from central and South America, Africa and South Asia, the epidemic is on the rise.
Countries in Europe, North America and Southeast Asia should continue to adopt public health and social measures, as well as comprehensive strategies such as surveillance measures, to ensure that the epidemic remains on a downward trajectory and that a second peak does not occur immediately.
Now, climate is not as important as expected.
A virus that doesn’t play by the rules
Seasonal weather affects viruses, most notably influenza viruses.
This is one of the most common and well-studied viruses in the world, and the results help explain the relationship between climate change and viruses.
In temperate regions, influenza is highly seasonal and tends to peak in winter.
Researchers believe flu viruses can survive better in cold, dry conditions.
The term “seasonal flu” is not unfounded.
In addition to the virus being more active in the cold, some researchers believe that human-to-human transmission is more likely here as people gather indoors to escape the cold weather.
Another controversial theory is that cold weather weakens the immune system.
The immune system is our natural defense against harmful substances.
As the virus enters the body through the respiratory tract, it USES human cells to make more copies of the virus.
Injured cells release signaling proteins called cytokines that communicate with the rest of the body to activate an immune response against foreign invaders.
Shu yuelong analysis, based on previous studies, influenza viruses are sensitive to temperature and humidity.
But that does not mean that transmission will be affected only by climate.
In 2009, for example, the outbreak occurred in the summer.
In historical pandemics, transmission of the virus often does not follow seasonal patterns.
For example, the Spanish pandemic peaked in the summer and most outbreaks occurred in the winter.
This suggests that the spread of the virus depends not only on the environment, but also on human behaviour once the virus has spread into human communities.
In Europe, for example, the spread of the measles virus increases when schools reopen and decreases during holidays when there is less contact between children.
Because the virus that causes the COVID-19 pandemic is new, much remains unknown and controversial.
But all sides agree that once transmission begins in the community, the connections between people drive the spread of the virus.
Stopping person-to-person contact is a more effective way to reduce virus infection.