Review of innate immunity, vaccines, and variants in SARS-CoV-2 reinfection

The coronavirus disease 2019 (COVID-19) pandemic is an ongoing global health problem caused by the new coronavirus severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2).

Many rigorous studies have been conducted to understand the etiology and infectivity of SARS-CoV-2. Despite all these efforts, many areas, such as SARS-CoV-2 reinfection and reactivation, have not yet been investigated.

More comprehensive studies are needed to assess the potential for reinfection and its potential risk factors.

Literature review of COVID-19 reinfection

In the literature review article published in Journal of Community Hospital Internal Medicine Perspectives, US authors conducted a thorough investigation of previous studies and case reports of SARS-CoV-2 reinfection. This review describes the role of innate immunity, vaccines, and SARS-CoV-2 mutants in reinfection.

Definition of reinfection

According to the Centers for Disease Control and Prevention (CDC), reinfection is “more than 45 days in highly suspicious cases of COVID-19 disease, more than 90 days in asymptomatic cases, or two in low-infection cases. It is defined as “infection of an individual with a different strain of virus”. Doubt “.

In addition, some studies define reinfection as having a negative test between two positive SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) tests, in addition to genotypic changes. ..

This review examines reinfection of individuals tested for SARS-CoV-2 using RT-PCR during the first pandemic wave prior to June 2020, from September to December 2020. The contraction of SARS-CoV-2 was evaluated according to the research group of SARS-CoV-2.

A study by Tillett et al. Two nasopharyngeal RT-PCR reports within a two-month gap discussed the first case of reinfection in the United States in a 25-year-old man who revealed a genetically distinct variant of SARS-CoV-2. ..

Another study by Hall et al. A previous history of SARS-CoV-2 infection has been found to reduce the risk of reinfection by 83%, and its protective effect can last up to 5 months.

Similarly, many reports have been published on the properties and duration of immunity that play an important role in reinfection.

Acute sequelae of SARS-CoV-2 infection

Patients with COVID-19 experience multiple symptoms of inflammatory injury and immunological dysregulation 4 weeks after the onset of an infection known as the acute sequelae of SARS-CoV-2 infection (PASC), always as a reinfection. Will be recognized. Therefore, understanding the difference between PASC and reinfection is key to managing COVID-19.

Reinfection and vaccination

The US Food and Drug Administration (USFDA) has approved several vaccines targeting the SARS-CoV-2 spike glycoprotein. A double dose regimen with Pfizer / BioNTech and Moderna / National Institute of Allergy and Infectious Diseases (NIAID) is approximately 95% effective in preventing symptomatic COVID-19, and a single dose regimen with Johnson and Johnson Janssen Biotech vaccine. It is 65.5. % effective.

Other vaccines such as Kovacin, AstraZeneca / Oxford, Sputnik V vaccine Effectiveness of In other parts of the world, 78%, 70.4% and 91.6% are approved, respectively. However, some vaccines were developed in China, while others are still in various stages of clinical trials.

From December 2020, new concerns including SARS-CoV-2 B.1.1.7 (alpha), B.1.351 (beta), B.1.617.2 (delta) P.1. (Gamma), B.1.427 and B.1.429 (Epsilon), and now B.1.1.529 (Nu) have emerged, with mutations in all receptor-binding domains. Spike protein.. Therefore, the emergence of various SARS-CoV-2 variants leads to uncertainty about the efficacy of the vaccine.

Antibodies and reinfection

In the majority of COVID-19 patients, immunoglobulin G (IgG) and IgM levels are elevated after the onset of symptoms. However, some infected patients do not develop antibodies for some unknown reason. Antibody levels in patients with severe COVID-19 are stronger than those found in patients with mild or asymptomatic infections. Antibody levels begin to decline within 60-90 days after the onset of infection. Immunity from these antibodies lasts as long as 7 to 12 months, according to some reports. Study by To et al.Reinfection was found to be determined by an increased immune response by IgG Neutralizing antibody And lack of IgM antibody.

Conclusion

The review concluded that the antibody response determines the lifespan of SARS-CoV-2 immunity and reinfection. To better understand this concept of reinfection, it may be helpful to determine the role of the vaccine in reinfection with various strains. The authors propose a more comprehensive study of the patient’s viral load, viral genotype, antibodies, and immune status to confirm true reinfection. In patients with asymptomatic infections, the potential for reinfection or reactivation should be assessed.