Questions are raised for Co-infection of COVID-19 variants in many countries

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Questions are raised for Co-infection of COVID-19 variants in many countries

Questions are raised for Co-infection of COVID-19 variants in many countries.

Many countries have reported co-infection of COVID-19 variants. What questions are raised?

The COVID-19 not only can be infected twice, but also can be co-infected. At present, Brazil, Portugal, the United Arab Emirates and other regions have found that a host is infected with multiple new coronavirus variants at the same time.

Some scientists have studied the replication rate and interaction of three different variants under single infection and combined infection, and found that there may be a synergistic effect between the viruses.

Will the patient’s condition worsen after co-infection? Will it increase the probability of genetic recombination and promote further mutation of the COVID-19? The reporter combed through relevant academic articles and connected infectious disease experts and virology experts to explain doubts.

Questions are raised for Co-infection of COVID-19 variants in many countries

Questions are raised for Co-infection of COVID-19 variants in many countries

Multiple countries found that patients were infected with multiple new coronaviruses at the same time

Once infected with the COVID-19, it can be re-infected, or even infected with multiple COVID-19 variants at the same time. Following the emergence of COVID-19 variants such as breakthrough immunity and secondary infections, there have been cases of co-infection of COVID-19 variants found in many countries.

An article published in the journal Microorganisms Dynamics of a Dual SARS-CoV-2 Lineage Co-Infection on a Prolonged Viral Shedding COVID-19 Case: Insights into Clinical Severity and Disease Duration reported a case of a 17-year-old Portuguese woman who was infected with two COVID-19 variants at the same time Physical condition. The woman was seriously ill, was hospitalized twice, and was admitted to an infectious disease ICU.

Similar cases have also been found in Brazil. An article included in the journal Virus Research, Pervasive transmission of E484K and emergence of VUI-NP13L with evidence of SARS-CoV-2 co-infection events by two different lineages in Rio Grande do Sul, Brazil, introduced the first report of new coronavirus B .1.1.28 (E484K) and other lineage variants had a co-infection event involving two patients.

In addition to a single case, there are also relatively large-scale related studies. As mentioned in the scientific report Genomic epidemiology of SARS-CoV-2 in the UAE reveals novel virus mutation, patterns of co-infection and tissue specific host immune response, published in Nature, the study will be conducted on May 9th and June 29th, 2020. The personnel collected the sequencing information of 1067 nasopharyngeal swab samples in the United Arab Emirates and found that at least 5% of them were infected with multiple clades of the COVID-19 at the same time.

Exacerbate the symptoms or not have much effect? Cases are still lacking

These cases of co-infection were found to show varying degrees of illness.

Two patients found in Brazil who were co-infected with the COVID-19 variant B.1.1.28 (E484K) and other pedigrees showed typical mild to moderate flu-like symptoms and a good prognosis without hospitalization and can recover on their own.

The 17-year-old woman in Portugal is in a serious condition. He had a 9-day history of persistent fever, dry cough, pleuritic chest pain, and vomiting at the time of medical treatment. Blood pressure was stable, but shortness of breath, hypoxia, CT showed extensive bilateral subpleural ground glass shadows.

Due to worsening breathing, the patient had received high-flow nasal oxygen therapy, which did not improve, and was further treated in the infectious disease intensive care unit. During the hospitalization, she also complained of symptoms such as left upper limb pain and worsening chest pain.

After the first hospitalization, the patient was admitted to the hospital for the second time nearly two months later.

Symptoms included headache, fever, myalgia, and chest pain. This symptom lasted for a short time. The researchers believe that the co-infection may have caused the case to be more severe and the virus to fall off for a longer time.

Some experts believe that from the current searchable professional articles, there are few relevant clinical cases found internationally, and whether co-infection will aggravate symptoms requires further research.

Theoretically speaking, multiple variants are infected at the same time, and if there is an effect between the variants to promote replication, it is equivalent to the increase in the number of enemies the human body has to deal with, and the immune response may aggravate, leading to aggravation of the disease, but aggravating the disease. There can be many reasons for this, and it is more difficult to define.

Questions are raised for Co-infection of COVID-19 variants in many countries

What is the cause of co-infection? Is it unique to the COVID-19?

According to Jin Dongyan, a virology expert at the University of Hong Kong, it is normal for patients to be infected by more than one virus. Co-infection of COVID-19 variants is relatively rare, but it is not a concern.

He analyzed several possibilities. For example, soon after the patient is infected with the first variant, the human body has not yet established a corresponding immune response, another virus infection occurs; it is also possible that the infected person has immune deficiency and is not easy to clear the virus, but this kind of person is a minority .

Jiang Rongmeng introduced that from other viruses, co-infections occur from time to time. For example, there are four subtypes of influenza A, B, C, and D.

Patients can be infected at the same time or successively without cross-immunity with each other; the four subtypes of dengue fever will not form cross-immunity with each other.

In contrast, the variants of the COVID-19 that are of concern are not large, and there is no real subtype at present, but the genetic variants at key points do have the ability to resist the virulence, transmission and even neutralizing antibodies of the variant. Had an impact.

The authors of the aforementioned Brazilian study pointed out that the possibility of co-infection adds new factors to the interaction between the immune response system and the mutation of the COVID-19.

Consider identifying the frequency of co-infections in clinical samples, including detailed analysis of the cells and humoral responses of the infected person, in order to better understand the causes and consequences of co-infections.

Competition or cooperation? Variant behaves differently

They are all new coronaviruses, and the degree of “compatibility” may also be different.

With the emergence of co-infection cases, some scientists have begun to study the replication rates and differences of different variants in the case of single infection and co-infection.

A research team composed of Kin-Chow Chang, Sarah Al-Beltagi, etc. of the University of Nottingham studied the relevant situations of Alpha, Beta, and Delta variants.

The report is entitled Emergent SARS-CoV-2 variants: comparative replication dynamics and high sensitivity to thapsigargin, published in the journal VIRULENCE.

The researchers found that among the three viruses, delta has the highest replication rate and can spread most to contact cells.

The replication rate of progeny viral RNA 24 hours after infection is more than 4 times that of alpha and 9 times that of beta. ; In co-infection, Delta can promote the replication of other viruses, and its own replication is inhibited to a certain extent; Alpha-Delta and Alpha-Beta co-infection can produce a synergistic effect, and the total offspring RNA output is greater than the sum of the corresponding single infection .

“The interactions between organisms are very complicated. Some promote each other, and some inhibit each other. These are basic problems.” Jiang Rongmeng said. For example, hepatitis B virus and hepatitis C virus have an inhibitory effect, and some patients are infected with both. Virus, hepatitis C is treated, and hepatitis B virus becomes active because the inhibitory effect of hepatitis C on hepatitis B is reduced; on the contrary, there is also an antibody-dependent enhancement effect (ADE), after infection once, the second infection of other subtypes of the virus In contrast, antibodies can promote infection rather than inhibit it. This phenomenon is reflected in dengue fever.

He also said that the phenomenon found in the laboratory may not cause major clinical problems, otherwise it should behave in the real world.

In the above-mentioned foreign studies, some authors said that as the COVID-19 epidemic continues, more cases of co-infection and secondary infections will be found, which will help clarify whether ADE will cause a more serious course of the disease.

Will it increase the probability of genetic recombination and bring challenges to prevention and control?

Viruses are constantly mutating, and genetic recombination is one of the ways to promote greater mutations. When humans co-infect two variants, will it increase the genetic recombination of the two variants and expand the mutation?

The article Co-infection, re-infection and genetic evolution of SARS-CoV-2: Implications for the COVID-19 pandemic control published in the Journal of Cancer Biology mentioned that coronaviruses usually have a higher recombination rate, while human hosts There is still a lack of understanding of virus recombination.

When host cells are infected with different variants or lineages of the same virus, recombination events may occur.

Jin Dongyan pointed out that there is no need to worry too much about this issue at this stage.

“From now on, the mutation of the new coronavirus is still relatively slow, and the gap between Delta and Alpha is very small. Under such similar circumstances, even if genetic information is exchanged and recombination occurs, it may not be harmful.

It does not necessarily affect transmission and virulence, or even survival.” He said that the phenomenon of co-infection should attract the attention of scientists.

However, compared with the recombination between new coronavirus variants, the academic community is more worried about the difference between different viruses. Recombination, such as MERS coronavirus and new coronavirus, among them, the mortality rate of MERS coronavirus can reach as high as 30%.

At present, cases of co-infection of the two viruses have been found in the world, but fortunately, there has not been a phenomenon of gene recombination. In the future, relevant scientific monitoring should be strengthened.

Questions are raised for Co-infection of COVID-19 variants in many countries

(source:internet, reference only)

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