In people’s cognitive journey against the virus, there is a misperception that, having been infected with a certain virus, it is certain that all strains of the virus are immune. This misconception needs to be corrected in the context of the ever-changing evolution of the virus today.
In the case of the new coronary virus, for example, since its inception, variations have continued on a global scale, with different strains, such as Alpha, Beta, Gamma, Delta and Omikron, coming in. When a person has contracted the original strain of the new coronary virus and recovered, a specific immune response to the strain occurs in the body. The B lymphocytes in the immune system produce specific antibodies, which are like precision “missiles” that identify and combine primitive strains to prevent their intrusion into human cells; and, at the same time, T lymphocytes are activated, which can directly kill cells infected by the virus or regulate the immune response by releasing cell factors. However, when faced with a variant, the situation becomes complex.
There have been changes at the genetic level in the strains of virus mutations, which may lead to changes in the antigen structure on the surface of the virus. For example, there are several mutations in the Omik variants on stingy protein. Protein is a key “key” to the invasion of human cells by a new coronary virus and an important target for the immune system to recognize the virus. Antibodies induced by the original strain infection may not be effectively identified and integrated by mutation strain mutations, thus enabling the strain to successfully invade human cells without partial immune defence. It’s like a lock has been modified and the original key is hard to open. Research has shown that some of the recovered persons who have been infected with the original strain are still at risk of re-infection in the face of the Omikon variant.
Not only is it a new coronary virus, but also a flu virus. The influenza virus varies every year, creating different strains of poison. The annual influenza vaccine also needs to be updated in response to changes in the epidemic strain. One person has been infected with a strain of influenza last year and has gained immunity, but this year another strain of influenza after a mutation is still at risk. This is due to the differences in antigens between different strains, which have significantly reduced the immunization protections established by previous infections.
In terms of immunological principles, there is a certain degree of specificity in the immunological memory of humans in response to viral infections. This specific immune memory is based on the antigen characteristics of the first infection. When the antigens of a variable strain differ significantly from the original virus, the immune system needs to be re-identified and responded to, and the process takes time and may not be able to remove the virus as quickly and efficiently as when the first infection occurs. In addition, there are individual differences in the intensity and duration of human immune responses. Factors such as age, health status and underlying diseases affect the functioning of the immune system. Older persons, children and people suffering from chronic diseases have relatively weak immune functions, and even if they are infected with a virus, resistance to the strain may be worse.
In the context of the continuing variability of the global virus, we cannot afford to be lightened by a single infection. Even when a virus has been infected, public health advice, such as wearing a mask, maintaining social distance, washing hands, enhancing ventilation, etc., is required. For some high-risk groups, such as health-care workers, the elderly, the under-immunized, etc., timely vaccination is an important measure to enhance protection against viral mutation. Vaccines can stimulate a broader immune response from the human immune system and, while the infection of mutated strains cannot be completely eliminated, can reduce the severity of infection and mortality.
An infection with a virus does not mean that all the strains of the virus have an impeccable immunity. We should take a scientific approach and properly understand the complex relationship between viral variability and immunization and actively take comprehensive measures to respond to the changing threat of the virus and to safeguard our health and that of others.
