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The new coronavirus began to spread in December 2019 and has since spread throughout the world, affecting 187 countries and territories and infecting more than 3.18 million people. However, the behavior and mechanism of the virus, even if it provides adaptive immunity, remains unclear. There have been reports of reinfection outside of South Korea and Japan.
Now, a team of scientists at Columbia University’s Mailman School of Public Health aimed to shed light on the issue of protective immunity against SARS-CoV-2 (coronavirus of severe acute respiratory syndrome 2) and whether patients recovered can become infected again. The research is published on the prepress server medRxiv *.
The team found that endemic human coronavirus reinfections are not uncommon, even within a year of the previous infection. They studied four common human coronaviruses, excluding SARS-CoV-2.
Human coronaviruses, HKU1, 229E, OC43, and NL63, cause a wide range of respiratory diseases, including pneumonia. However, these coronaviruses can only cause mild to moderate disease and occur occasionally, unlike SARS-CoV-2, which was first reported in China.
“As the COVID-19 pandemic progresses, infecting millions of people worldwide, a key question is whether people are likely to repeat the infection. Evidence of endemic coronaviruses suggests that immunity is short-lived, and reinfection is common within one year, with the severity of symptoms possibly more genetically dependent on the presence or absence of antibodies. Research on endemic coronaviruses, along with findings for SARS and MERS, provide a context for understanding protective immunity against repeated SARS-CoV-2 infections, “said Dr. Jeffrey Shaman, science professor at the Enviromental health.
Understand the risk of repeated infection
Viral respiratory infections in humans, which can range from common colds to severe respiratory illnesses, place a huge global health burden on developing countries. Human coronaviruses (HCoV) are linked to a wide range of upper respiratory tract infections and, in some cases, lower respiratory tract infections. Although they come seasonally, only a few long-term studies looked at the prevalence of HCoV strains and their clinical manifestations.
The current global pandemic has negatively affected not only developing countries, but even first world countries such as the United States, the United Kingdom, and other European countries. Determining reinfection in SARS-CoV-2 is essential to prevent further spread of the virus. Scientists believe that by studying reinfection rates in other human coronaviruses, they can provide information if the phenomenon occurs in COVID-19.
There may be two processes that may be responsible for short-lived immunity to endemic coronaviruses. First, the decline in antibodies and memory cells over time can affect a person’s immunity to a human coronavirus, and there may be an antigenic drift or mutation from the virus or pathogen that allows them to evade established immunity against previous strains. .
Children most likely to be reinfected
To arrive at their findings, the researchers used data from proactive sampling in New York City between fall 2016 and spring 2018. They combined weekly collection of nasal swabs and self-reports of respiratory symptoms from 191 participants. The team used the data to investigate the profile of recurrent infections with endemic coronaviruses.
Of the 191 participants, 86 tested positive at least once during the study for 144 any coronavirus infection. About 48 patients tested for OC43, 31 tested positive for 229E, 15 tested positive for NL63, and 28 tested positive for HKU1.
Among human coronaviruses, OC43 is the most diffuse, and the probability of testing positive after 80 weeks in the study was 0.47. Furthermore, the least frequently isolated coronavirus was NL63. The average time between reinfection was approximately 37 weeks, and among the 12 people who tested positive twice, nine were children between one and 9 years old, while three were adults between 25 and 34 years old.
“This study provides evidence that reinfections with the same endemic coronavirus are not atypical in less than a year, and that the genetic basis of an innate immune response may be a greater determinant of infection severity than memory. immune system acquired after a previous infection, “The researchers concluded in the study.
The team revealed that when reinfection occurs, it is not linked to less severe symptoms. Instead, certain genetic factors can contribute to the severity of an infection. This means that those who were asymptomatic during the first infection did not experience symptoms even during subsequent infections. Additionally, members of the same family reported similar symptom severity.
*Important news
medRxiv publishes preliminary scientific reports that are not peer reviewed and are therefore not considered conclusive, guide clinical practice / health-related behavior, or are treated as established information.
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