The true statement that the new crown virus and hepatitis B are the same is very outrageous.

More important points:

1 Hepatitis B is divided into acute and chronic. Chronic hepatitis B is a chronic infection among persistent viral infections. The chronicity of hepatitis B virus is due to the presence of cccDNA (covalently closed circular DNA), and it is difficult to remove, so long-term medication control is required. The new coronavirus is an RNA virus, which is an acute infection without cccDNA, which is very different from chronic hepatitis B virus.
2 Some patients with chronic hepatitis B cannot detect protective antibodies because the virus has been replicating, and the progeny virus produced directly "absorbs" the protective antibodies. The new crown virus is an acute infection. For people who clear the new crown virus, there is no such thing as a persistent infection without antibodies.
3 At present, some patients with new coronavirus infection are positive for nucleic acid detection after discharge from hospital. The specific mechanism is not clear. There is a large possibility that the virus is discharged during the recovery period, and it may be that the virus enters the immune pardon part of the body. It is most likely caused by immunosuppressive drugs (such as corticosteroids) used in the treatment of patients. At present, there is a very low probability that the new crown virus will become chronic.
Checker: VC | PhD in Pathogen Biology, Popular Science Author

Recently, a chat record about "new crown virus is the same as hepatitis B" has been widely spread on social media. The chat record said that "new crown virus has the same characteristics as hepatitis B. Once infected, if there is no antibody, you need to take medicine for life" "Some patients are discharged Post-positive is that there is no antibody. Once the antiviral treatment is stopped, the virus will make a comeback. "The new crown virus will become a chronic disease, and children will have to get an additional new crown vaccine." Are these claims correct? Is the new crown virus the same as hepatitis B virus?

Hepatitis B is divided into acute and chronic. Chronic hepatitis B is a chronic infection among persistent viral infections, while neocrown virus is an acute infection, which is different from hepatitis B virus.

Let's look at a few concepts first.

The so-called persistent viral infection refers to the existence of the virus in the body for several years or decades, and the body can or can not develop the disease. There are many types of persistent viral infections, such as latent infection, chronic infection (Chronic infection) and Slow virus infection.

Latent infection is that after viral infection, viral genes exist in cells, and some viruses dormant in certain tissues and organs, but do not replicate. They can be activated and restart replication under certain conditions, and symptoms will occur at this time. Herpes simplex virus (HSV) (bulb on the corner of the mouth) is the most common latent infection. After the virus infects, it lurks in the ganglia. After the body's immunity is weakened, it moves along the nerve fibers to the inner skin tissue to replicate, and then symptoms appear.

Chronic infection is that the virus cannot be completely removed in time after the infection, and the virus can be continuously detected in the blood. The patient's symptoms may be mild, but they will recur and persist. The most common are hepatitis B (hepatitis B) and hepatitis C (hepatitis C).

Lentivirus infection is a virus that has a relatively long incubation period. After months, years, or even decades, symptoms may continue to worsen and eventually lead to death. HIV that causes AIDS is a slow-onset virus infection, but it is also characterized by latent and chronic infections.

Hepatitis B is divided into acute and chronic. Most adults infected with acute hepatitis B will recover and gain immunity, and about 5% of adult patients with acute hepatitis B will become chronically infected. Chronic hepatitis B belongs to the persistent viral infection mentioned above. Chronic infection. The new coronavirus is an acute infection with rapid onset and rapid progress. The course of disease is usually several days to several weeks, which is different from hepatitis B virus.

Some patients with chronic hepatitis B have no antibodies because the virus has been replicating, and the new crown virus is an acute infection that produces antibodies

The reasons why the aforementioned hepatitis B and other viruses can cause persistent infection are nothing more than these four factors: the virus coexists with the host for life; the virus regulates the body's immune system; the virus directly infects immune cells; the virus enters the immune amnesty area. The chronicity of hepatitis B virus is due to the presence of cccDNA (covalently closed circular DNA), and it is difficult to remove.

The genome of hepatitis B virus is incomplete double-stranded DNA. After entering the cell, the DNA will enter the nucleus and will be repaired into cccDNA. cccDNA remains in liver cells until the cell is destroyed. After the acute hepatitis B infection resolved, there was no new hepatitis B virus in human blood, and liver cells with cccDNA no longer existed. After the chronicity of hepatitis B, it means that the hepatitis B virus persists in the blood, and most liver cells will be infected by the virus. Therefore, it is basically impossible to completely remove cccDNA, and there will always be progeny virus generation, and the amount is huge, which requires lifelong medication pressing.

Unlike hepatitis B virus, neocrown virus is an RNA virus, does not exist cccDNA or can integrate into the human chromosome genome like HIV, so it is impossible to persist by maintaining a copy of genomic DNA. Looking at hepatitis C virus HCV again, there are two chronic mechanisms: one is that the frequency of HCV mutations is very high, and the other is that microRNA-122 of liver cells binds to the HCV virus genome, thereby maintaining a stable genome. The mutation frequency of New Coronavirus is much lower than that of HCV. The genome is enveloped by nucleocapsid protein (N protein). N protein is relatively conservative and stable, so it does not maintain the existence of the genome through microRNA.

This is the essential difference between new crown virus and persistent infectious viruses such as hepatitis B and C.

As for some chronic hepatitis B patients without antibodies, it is because the virus has been replicating, and the progeny virus produced will directly deplete the neutralizing antibody, the surface antigen antibody (full "absorption", the specific mechanism is not clear), so the test is not Here. The new crown virus is an acute infection. As long as it is infected by a foreign pathogen, it will definitely produce antibodies, regardless of whether the antibodies are protective. For those who have cleared the new coronavirus, the level of antibodies against nucleocapsid protein (N protein) may be high, and the level of neutralizing antibodies against spike protein (S protein) may be low, but there will not be no antibodies, just Maybe different people have different levels of neutralizing antibodies due to individual differences.

News media have reported cases where antibodies are not produced. Such a situation rarely occurs. The possible reason is that lung macrophages cannot migrate to lymph nodes to stimulate B cell activation, or the special environment of local infection in these patients cannot stimulate the lungs. The activation of peripheral macrophages requires further research to determine the details.

In addition, add another knowledge point, although hepatitis B is a chronic disease infectious disease, there is also an acute transition to a chronic process (below).

For HBV, can you finally rely on the serological "two and a half" test (also usually combined with viral DNA testing) to see what state the patient is in, whether it is an acute infection or a recovery period?

For "big three suns", if you turn to "small three suns", the body tends to recover (23 in the figure above). For most people who have been vaccinated, only antibodies against surface antigens (anti-HBs) are positive (7 in the figure above). If there is no treatment, or if it becomes chronic, it will appear that the body has no surface antigen antibodies (anti-HBs), while the others are positive (4 in the figure above).

New crown virus may persist in the human body for a period of time, but the possibility of becoming chronic is very low

As mentioned earlier, neocoronavirus infection is an acute infectious disease that is not the same as chronic hepatitis B. However, some people are still worried that the new crown virus will become chronic and thus persist in the human body. The circulating chat records also mentioned this.

Regarding the persistent infection of acute viruses such as the new crown virus, we can refer to the previously outbreak of Zika virus (ZIKV) and Ebola virus (EBOV).

Both viruses' RNAs have been detected in patients who have partially recovered for a long period of time. The RNAs of these viruses are generally found in different immune amnesty sites (such as semen). There are also cases of Ebola patients with recurrent Ebola encephalitis 9 months after discharge.

Why is there a persistent infection? Back to the factors that we have mentioned in the past: the virus coexists with the host for life; the virus regulates the body's immune system; the virus directly infects immune cells; the virus enters the immune amnesty zone. For Zika virus and Ebola virus, the virus is likely to persist in the body for some time by entering the immune amnesty site.

So, can the new coronavirus persist in this way in the human body? There is already some evidence that viral nucleic acid returns to the hospital after discharge. The specific mechanism of this phenomenon is currently unknown, and there may be several explanations:

1. A positive nucleic acid test does not mean that there is a live virus. It is not clear how infectious it is at this time, and it is necessary to isolate the virus to determine it.

2. Even if there is a virus, it depends on the amount of virus excreted. It is likely that low-titer viral shedding is very common during recovery. This possibility varies from person to person.

3. Like Zika virus and Ebola virus mentioned earlier, the new crown virus enters a special part of the immune system to persist in the body for a long time, but this cannot be equated with chronic infection.

4. In the end, it may be that patients use immunosuppressive drugs (such as corticosteroids) during treatment, causing the virus to persist in the body for a period of time, such as directly infecting immune cells.

As for whether the new coronavirus that people are very concerned about will change from acute to chronic like hepatitis B, I think the possibility is very low, but it does not rule out that the new coronavirus will be in the semen like some cases of Ebola or Zika infection. It is present in body fluids for a long time, so patients with current Fuyang should be observed subsequently.