If it is proved that the coronavirus has a more extended incubation period of 14 days, the consequences may prove drastic.
How does the causative agent react to heat, cold, and moisture?
And why are women more protected than men?
So far, it was supposed that the incubation period of the disease caused by the new coronavirus-i.e., the time between infection and the appearance of the first symptoms-lasts from 2 to 14 days.
These were at least the guidelines given by the World Health Organization (WHO), the German institute “Robert Koch” and the German Ministry of Health.
That’s why people with a suspicion of coronavirus are quarantined for two weeks.
The whole epidemic came from Hubei province, China.
The authorities there claim that the first symptoms of the virus in a 70-year-old man expressed on the 27th day.
Prof. Dr. Christian Drosten, a coronavirus expert from the Berlin Centre for Infections, believes that such individual cases are not indicative.
According to him, there is no need to change the indications regarding the incubation period.
Different organisms react differently
“Patients react differently to the causative agents of infection, which means that the incubation period can vary significantly,” says the molecular virologist Thomas Pichmann.
Professor Dr. Jonas Schmidt-Chanasit, at the University of Hamburg, argues that individual cases of a more extended incubation period have already been observed.
However, most of the infected expressed the first symptoms of the coronavirus after a week.
Gradually, a sufficient number of patients were gathered to make more precise conclusions.
The incubation period with some of them is longer-up to a month, but the majority of people get sick as early as the first week after infection.
What does the more extended incubation period mean?
If the incubation period turns out to be longer than the previously accepted 14 days, this would dramatically affect the efforts to contain the outbreak.
At least because the adopted quarantine of 14 days will not be enough now, it could be that thousands of Chinese employees returning to work after a forced two-week leave can trigger a second infectious wave.
In Japan, Health minister Katsunobu Katō asked the passengers of the cruise ship “Diamond Princess” to stay under home quarantine two more weeks after the 14-day quarantine on the board.
The measure is also required because, in two Australians, the virus was discovered when they returned home after they had tested negative samples on board.
People without symptoms can also be carriers?
It is also alarming that in some patients, it remains entirely unclear how they got infected, i.e., the source of the infection cannot be established.
For example, some people were neither in China nor had direct contact with a patient who had been confirmed that was infected with the coronavirus.
This is supporting the thesis that people without any symptoms also can be carriers of the infection.
How resistant is the virus?
Many people hope that the coronavirus will turn out to be no different from influenza viruses, which will resolve over the onset of warmer weather.
This is observed every year – with the end of winter and the flu waves pass by.
But is it the case with the new coronavirus?
The fact is that respiratory viruses thrive well in the cold weather.
“Viruses last longer at low temperatures–like food products that are best preserved when they’re in the fridge,” explains Thomas Pichmann.
And indeed – in the northern hemisphere, where it’s winter now, the conditions are favorable for the spread of the virus.
In cold and dry weather
The warmer the weather is, the harder it is for the viruses to survive.
“The coronavirus has a lipid shell, i.e., it is covered by a fatty layer, which is not particularly resistant to heat, “explains the expert-virologist.
It means that in rising temperatures, the virus dies relatively quickly.
For example, the norovirus is significantly more resistant because it is composed mainly of protein.
Air humidity is another crucial factor for respiratory viruses.
If the causative agent of infection is thrown out of the respiratory tract into the atmosphere, for example, after sneezing, it remains to float in the air in the form of small droplets containing viruses.
“In the cold and dry days in the winter, these droplets survive longer in the air than at high humidity,” says Pichmann.
Women are more protected
Fever, pains, and chills are typical symptoms of viral disease and, at the same time signifies that the body fights against invaders.
How successful is this counteract depends not only on the age and health of the infected but also on his/her gender.
The latest results confirm that women infected with coronavirus have better chances than men: mortality rates for women are only 1.7%, while men are 2.8%.
The reasons for this are genetic, says Pichmanm: “Some genes that play an essential role in the body’s immunity –those responsible for the recognition of viral infections are encoded in the X-chromosome.
And since women have two X chromosomes, and men only have one, the former is better protected.
Also, female hormone estrogen helps to better protect against viral diseases.