Exposure to the common cold coronavirus causes SARS-CoV-2. increases the immune response against

The study was carried out by researchers from the Charité-Universittsmedizin Berlin, the Berlin Institute of Health at Charité (BIH) and the Max Planck Institute for Molecular Genetics (MPIMG).

Researchers also report that this ‘cross-reactive immunity’ tends to decline with age. This phenomenon may help explain why older people are more vulnerable to severe disease and why their vaccine-induced immunity is often weaker than that of younger people.

In an earlier study, researchers indicated that individuals who have no prior exposure to SARS-CoV-2 have ‘T helper cells’ that may have been generated to combat the harmless common cold coronavirus and to fight against the two viruses. Because of their similarities between, these cells also attack the novel coronavirus. This ‘cross reactivity’ hypothesis has been confirmed by several studies.

“Our belief at the time was that cross-reactive T helper cells have a protective effect, and that prior exposure to endemic (ie long-established and widely circulating) coronaviruses reduces the severity of COVID-19 symptoms. ,” the study’s (and previous study’s) first author, Dr. Lucie Loyle, C-M (‘Der Simulierte Mensch’ – literally ‘The Simulated Human’, a joint research space of the Charité and Technische University Berlin) and the BIH Center For regenerative both based on a researcher treatment (BCRT).

“However, the opposite could be true. With some viruses, a second infection involving a similar strain can lead to a falsely induced immune response and negatively impact the clinical course. In the present study, Berlin The based research team presents evidence to support their previous assumptions regarding the existence of a protective effect. According to their data, cross-reactive immunity is among the many reasons for the variability in disease severity seen with COVID-19. There may be one, but differences in vaccine efficacy seen in different age groups may also explain,” she said.

For the current study, researchers recruited individuals with prior exposure to SARS-CoV-2, testing them at regular intervals to determine whether they had contracted the infection. Of the nearly 800 participants, 17 persons tested positive. The study showed that the immune response against SARS-CoV-2 also involved the mobilization of T helper cells that were produced in response to the endemic common cold virus.

The researchers also showed that the quality of the immune response against SARS-CoV-2 was linked to the amount of cross-reactive cells. These cells were particularly effective at recognizing a certain region of the spike protein.

In both the endemic virus and the new coronavirus, this site was characterized by sequence similarities that were particularly well ‘conserved’. Corresponding author of the study, Dr Claudia Gieske-Thiel, Head of the Flow Cytometry Services Group at MPIMG, explained, “During infection with more harmless coronaviruses, the immune system forms a kind of protective ‘universal coronavirus’ memory. “

“Once exposed to SARS-CoV-2, these memory cells are reactivated and begin a response against the new pathogen. This may help to accelerate the initial immune response to SARS-CoV-2 and limit viral spread during the early stages of infection and is therefore likely to have a positive effect on the course of the disease,” Giske-Thiel said. .

However, Giesecke-Thiel said that this does not mean that exposure to the common cold virus can definitely protect a person from SARS-CoV-2, nor that it has so far changed the course of the epidemic. Changes because these underlying mechanisms are working. with everyone. This does not diminish the importance of vaccination.

The findings confirmed that the immune-boosting effects of cross-reactive T cells also occur following vaccination with the BioNTech Covid-19 vaccine. Like natural infection, the vaccine prompts the body to produce the SARS-CoV-2 spike protein (including its well-protected part) and introduce it to the immune system.

Analysis of the immune responses of 31 healthy individuals before and after vaccination showed that, while activation of normal T helper cells occurred slowly over the course of two weeks, activation of cross-reactive T helper cells was very rapid. . Within a week of vaccination.

Naturally, this also had a positive effect on the generation of antibodies. Even after the first dose of the vaccine, the body was able to produce antibodies against the protected portion of the spike protein, usually seen after booster vaccination. “Even after vaccination, the body is able to use at least some of its immunological memory – provided it has been in previous exposure to endemic coronaviruses,” said co-corresponding author Professor Dr Andreas Thiel, both from a charity based on C-M. The researcher said. and BCRT.

“This may explain the surprisingly rapid and extremely strong protective effect that we see after the initial dose of the COVID-19 vaccine, at least in younger individuals,” he said.

In the second part of the study, the researchers analyzed T helper cells in about 570 healthy individuals. Older participants had lower both the number of cross-reactive T cells and the strength of their binding interactions. According to the authors, this decline is due to normal, age-related changes. “Infection with an endemic coronavirus represents an advantage in young people, helping them fight off SARS-CoV-2 or develop immunity after vaccination. Sadly, this benefit is less clear in older adults,” Professor Thiel said.

“It is likely that a third (or booster) dose will be able to compensate for this weakened immune response, ensuring that members of this high-risk group have adequate immunity,” he said.

India’s cumulative COVID-19 vaccination coverage is over 684.6 million. To check the circulation of spurious vaccines in the country, the Union Health Ministry on Saturday issued guidelines for identification of spurious vaccines.

India recorded 42,766 new coronavirus cases with 309 deaths in the last 24 hours. The active caseload currently stands at 4,10,048, which contributes to 1.24% of the total positive cases in the country.

India has conducted over 53,00,58,218 cumulative tests so far. The weekly positivity rate is currently 2.62% and the daily positivity rate is 2.45%.

The Union Health Ministry said that more than 66,89,80,635 vaccine doses have been provided to the States/UTs so far and more than 15.6 million doses are in the pipeline.

More than 43.7 million unused vaccine doses are still available with the States/UTs to be administered.