Weather of Arabia - The world is following with concern the news of the new Corona virus mutant, especially the fast-contagious delta mutant, which has now spread in most countries of the world, and many of us wonder whether vaccination or previous infection will provide protection against these new strains!
A person can develop immunity (the ability to fight infection) in two ways: either after infection with a virus or through vaccination. However, immune protection is not always equal.
Immunity against the Corona virus between the body obtained from the vaccine can differ from the natural immunity in terms of the strength of the immune response or the length of time that protection lasts . Additionally, not everyone will have the same level of immunity to infection, while immune responses to vaccines are very consistent and nearly identical.
The difference in immune response between vaccination and infection appears to be greater when dealing with novel variants.
In early July, two new studies were published showing that COVID-19 vaccines, although slightly less effective than they are against older strains of the virus, still provide an excellent immune response against the new variants.
The researchers looked at how the antibodies bind to new variants of the coronavirus and found that people who were previously infected with the coronavirus may be more susceptible to infection with the new strains, while vaccinated people were less likely to be infected and more protected.
Immunity comes from the immune system's ability to remember the organism causing the infection. Using this immune memory, the body will know how to fight off the infection if it encounters the pathogen again.
Antibodies are proteins that can bind to the virus and prevent its invasion of the body, and T cells direct the removal of infected cells and viruses attached to the antibodies. These two are the basis of the mechanism of action of immunity.
The antibodies and T-cell responses of a person who has previously been infected can provide protection against reinfection. About 84% - 91% of people who develop antibodies to the original strains of coronavirus are mostly protected for 6 months from re-infection.
Even mild infections and people who did not develop symptoms during infection develop immunity, although their antibody production may be lower than those who felt symptoms of the disease. So for some people, natural immunity may be strong and long-lasting.
But one big problem is that not everyone will develop immunity after infection: about 9% of infected people do not have antibodies detected, and up to 7% of those infected do not have T cells.
For people who develop immunity, the strength and duration of protection can vary greatly. Up to 5% of people may lose immune protection within a few months.
Without a strong immune defense, these people are susceptible to infection again with the Coronavirus, some have been exposed to a second infection with COVID-19 one month after the first infection! Although it is rare, some people have been hospitalized or even died after being infected again.
Another problem is that people who were previously infected with the first strains of the pandemic may be more likely to be infected again with the delta mutant.
One recent study found that 12 months after infection, 88% of people still had antibodies that could prevent cultured cells from infecting the original variant of the coronavirus — but less than 50% had antibodies that could block the delta mutant.
Furthermore, an infected person may also be able to transmit the virus , even without feeling ill . New variants are particularly problematic in this case, as they are transferred more easily than the original strains.
COVID-19 vaccines generate both antibody and T-cell responses — responses that are much stronger and more consistent than immunity after a natural infection.
One study found that six months after receiving the first dose of the Moderna vaccine, 100% of people tested had antibodies against the virus, which is the longest period reported in studies published to date.
In a study looking at the Pfizer and Moderna vaccines, antibody levels were also significantly higher in people who had been vaccinated compared to those who had recovered from the infection.
Even better, a study showed that the Pfizer vaccine prevented 90% of infections after both doses — even with new variants, and lower infections mean people are less likely to pass the virus on to people.