According to CCTV news, at the Shanghai epidemic prevention and control press conference held today (8th), Zhao Dandan, deputy director of the Shanghai Municipal Health Commission, explained that Shanghai will continue to carry out the new coronavirus in response to the emergence of new coronavirus mutant strains in Shanghai. The gene sequencing of the virus samples, the sequencing results show that the virus genotypes of the infected people reported in the recent local epidemic in Shanghai are mainly Omicron BA.2 and BA.2.2 mutants, and no new mutants with stronger transmission have been found. .

Cold chain food has frequently tested positive for the covid recently. After the outbreak in Qingdao, the live new corona virus was isolated for the first time in cold chain food. Recently, 3 imported ice creams in Tianjin tested positive for the new corona virus.

There is no doubt that the virus can indeed be transmitted through cold chain food contact. Hearing this news, many people may wonder, how long does the virus have a lifespan on the surface of the item, or that the virus will not die and can only be killed with disinfectants?

How long is the lifespan of a virus attached to an object? Or will it never die and must be disinfected?
How long is the lifespan of a virus attached to an object?

The stability of a virus on the surface of the object can directly affect its ability to spread. Viruses with pandemic potential, such as Ebola virus and influenza virus, can survive on the surface of the object for a period of time and there is a risk of transmission.

The survival of the virus on the surface of the object is affected by a series of factors, including the type of virus, the load, the temperature, humidity, material of the object, ultraviolet rays, pH value, etc. As early as February last year, experts from the National Health Commission said that if the temperature and humidity are suitable, the new corona virus may survive in the environment for several days. Scientists have studied the survival time of the new coronavirus [. There are mainly the following:

1) Environmental materials

Some researchers have studied the survival time of the new coronavirus on aerosols and common materials in life, including aerosols, plastics (polypropylene), alloy stainless steel, copper and cardboard. When the ambient temperature is 21-23°C and the relative humidity is 65%, the new coronavirus can survive in the aerosol after nebulization for 3 hours. The new coronavirus is relatively stable on plastic and stainless steel surfaces and can survive for up to 72 hours. The specific survival time of the new coronavirus on the surface of the four materials is: copper (3.4 hours) < cardboard (8.45 hours) < stainless steel (13.1 hours) < plastic (15.9 hours). And British experts have also reported that the new coronavirus survives longer on non-permeable (waterproof) surfaces, such as stainless steel or plastic surfaces; and relatively short on permeable materials such as fabrics or paper towels.

2) Temperature and humidity

Different temperatures and humidity are also key to the survival of the virus. Some studies have found that when the average temperature is 8.72 ℃, it is most suitable for the spread of the new coronavirus. Studies have found that the new coronavirus can survive for up to a month in a super-saturated environment with a low temperature below zero and a relative humidity of 100%. Therefore, in winter, the weather is cold, and the epidemic is more likely to recur.

How long is the lifespan of a virus attached to an object? Or will it never die and must be disinfected?
Summarize

We don’t need to panic too much about a positive nucleic acid test such as cold chain food, because a positive nucleic acid test can only prove that there was a virus in the sampling place. means to test. However, under the background of the current global epidemic outbreak, for the sake of epidemic prevention, the disease control department will prioritize the storage and destruction of this batch of ingredients and notify the public. In fact, after the cold chain food has been imported for a long time, the virus on it has often been reduced in number and activity, and the infectivity is no longer high.

In short, we say that the new coronavirus can survive for a long time under the influence of the environment, but it will not exist forever, and the virulence and transmission of the virus will gradually weaken over time. For imported items, it is still necessary to sterilize some high-touch surfaces, wash hands frequently, and ventilate frequently.

When the human body is infected with viruses through body fluids, droplets and direct contact, after the incubation period, these viruses will proliferate and kill cells in the body. white blood cells to kill these viruses.

 

When the number of viruses is too large, a type of leukocyte with strong killing will start to attack indiscriminately, and the larger mononuclear leukocytes will directly phagocytose the virus and infected cells.

Next, macrophages and dendritic cells will join the fight, and the immune response will leave a large number of dead cells and tissue fluid left behind.

 

At this time, our body starts to sneeze or cough, and produces discomfort such as fever and fatigue, which is a signal from the body to let us rest.

Under normal circumstances, when we take medicine, the virus will decrease, and our body will gradually start to improve. However, when encountering a cunning and difficult virus, the physical condition will continue to deteriorate, and the immune cells will continue to kill normal cells in large numbers.

At this time, it is difficult for the cells in the body to maintain normal work, and extreme deterioration begins. At this time, special drugs and surgical treatment must be passed to assist the immune system and reduce the complications caused by decreased immunity.

After fighting the virus for a period of time, the dendritic cells will remember the virus’s information and tell the lymph nodes that the powerful T cells in the lymph will divide rapidly and head to the battlefield, and the infected cells will also self-destruct to suppress the virus.

 

Then some T cells will remember all the information of the virus and transmit it to B cells, and B cells will start to produce immunoglobulins (antibodies) to deal with these viruses.

When a new virus or virus mutation appears, the difficulty we face is that no one has produced antibodies to the virus we encountered for the first time, and the vaccines that artificially induce antibodies are too late.

However, the job of making antibodies is the job of “acquired immunity” in the immune system. The immune system, on the other hand, has “natural immunity” to fight foreign bodies, with or without antibodies.

 

Novel is new to “acquired immunity”, neither new nor old to “natural immunity”. That is to say, people whose natural immunity is active can recover quickly even if they are infected with a new virus.

 

Signals of LPS-induced antiviral effects

As a substance that activates natural immunity, LPS can activate natural immune active cells – macrophages. Macrophages eat virus-infected cells for processing. LPS can activate signals that induce antiviral factors (interferon beta, etc.) (*1). Therefore, eating more LPS-containing foods on a daily basis can prevent the new coronavirus and speed up recovery even if infected.

It has been two and a half years since the epidemic, what the future will be like, people need a reassurance, that is, when will this day be over, the virus is mutating, constantly updating and iterating, and human beings are also constantly injecting new vaccines, This is a war without gunpowder smoke. Will the new coronavirus disappear silently like the SARS virus?

In the open world environment, the war against the new coronavirus is no longer a matter of one country. Even if a country is cleared, the virus will not disappear as long as the vector carrying the virus exists. This is a war for all mankind, but Because of the policies of some countries to lie down early and enter herd immunity too early, they have virtually provided the virus with a good living space and the time it needs to mutate. The virus is extremely contagious, and it is a fatal blow to the elderly and the poor. Limited medical resources will inevitably lead to unequal distribution of medical resources.

In order to ensure the safety of people’s lives, the Chinese government maintains the “zero policy”, which is the most pragmatic policy. my country’s large population base is the most suitable for steady and steady development, especially in some remote areas and small cities with limited medical resources, and it is necessary to strictly guard against virus importation. , The new coronavirus is still in the research and experimental stage, this process may be a bit long, but I believe that this stage is far from reaching the conditions for herd immunity, and it is not as simple as treating the new coronavirus as a common cold. A period of time without hospitalization if you have the new coronavirus.

Self-testing reagents have appeared, the cost of virus detection will be lower and lower, and the dynamic management of the epidemic will gradually become a reality in the future. Some local governments will gradually eliminate the policy of killing chickens and taking eggs. The follow-up of the zero policy is that it means rejecting all foreign input carriers, so the dynamic management of the epidemic is the most suitable policy for the current national conditions.

The good news is that the proportion of asymptomatic infections in this outbreak in Shanghai has increased, and the number of unvaccinated deaths has increased, which is enough to show that the vaccine is effective. Therefore, we must encourage the masses to actively vaccinate. Humans and viruses are evolving together, and with the level of medical care. And with the in-depth development of virus mutation research, herd immunity will also become a reality.