A few weeks ago, a message appeared in the corner of my screen. “What do you think of the people who recently took COVID-19 to get the vaccine?” A friend of mine was eligible for a COVID – 19 vaccine, but she had recently overcome an infection with SARS – CoV – 2. More people are becoming eligible for vaccines each week – including millions of people who have already recovered from a HIV infection. coronavirus. Many are wondering if they need the vaccine, especially people who have already been infected.
I study the immune responses to respiratory infections, so I get a lot of these types of questions. A person can develop immunity – the ability to resist infection – by being infected with a virus or by receiving a vaccine. However, immune protection is not always the same. The strength of the immune response, the duration of protection and the variation in the immune response between people are very different between vaccine immunity and natural immunity to SARS – CoV – 2. COVID-19 vaccines offer safer and more reliable immunity than than natural infection.
Immunity after infection is unpredictable
Immunity comes from the immune system’s ability to remember an infection. Using this immune memory, the body will know how to fight if it encounters the disease again. Antibodies are proteins that can bind to a virus and prevent infection. T cells are cells that direct the removal of infected cells and viruses already bound by antibodies. These two are some of the main actors that contribute to immunity.
After a SARS-CoV-2 infection, a person’s T cell and antibody responses may be strong enough to provide protection against reinfection. Research shows that 91% of people who develop antibodies to the coronavirus are unlikely to be infected again for six months, even after a mild infection. People who did not show symptoms during the infection are also likely to develop immunity, although they tend to produce less antibodies than those who felt sick. Therefore, for some people, natural immunity can be strong and long-lasting.
The problem is that not everyone will develop immunity after a SARS-CoV-2 infection. Up to 9% of infected people do not have detectable antibodies and up to 7% of people do not have T cells that recognize the virus 30 days after infection.
For people who develop immunity, the strength and duration of protection can vary widely. Up to 5% of people can lose their immune protection in a few months. Without a strong immune defense, these people are susceptible to reinfection by the coronavirus. Some had second COVID attacks – 19 just a month after their first infection; and, although rare, some people have been hospitalized or even died.
A person who is reinfected can also transmit the coronavirus, even without feeling sick. This can put the person’s loved ones at risk.
What about variants? So far, there is no concrete data on the new variants of coronavirus and natural immunity or reinfection, but it is certainly possible that the immunity of an infection is not as strong against infection with a different variant.
COVID-19 vaccines produce a strong immune response in terms of antibodies and T cells, like the T cell in this photo. Photo via National Institutes of Allergy and Infectious Diseases / National Institutes of Health
Vaccination leads to reliable protection
COVID-19 vaccines generate antibody and T-cell responses – but this is much stronger and more consistent than immunity against natural infections. One study found that four months after receiving the first dose of the Modern vaccine, 100% of the people tested had antibodies against SARS-CoV-2. This is the longest period that has been studied so far. In a study that examined the Pfizer and Moderna vaccines, antibody levels were also much higher in those vaccinated than in those who recovered from the infection.
Better yet, a study in Israel showed that the Pfizer vaccine blocked 90% of infections after both doses – even with a variant present in the population. And a decrease in infections means that people are less likely to transmit the virus to people around them.
COVID-19 vaccines are not perfect, but they produce strong responses of antibodies and T cells that offer a safer and more reliable means of protection than natural immunity.
Infection and vaccination together
To my friend’s message, I immediately replied that she should get the vaccine. After being vaccinated, my friend would be comfortable knowing that she has effective and long-lasting immunity and less chance of spreading the coronavirus to her friends and family.
But more good news has emerged since I sent that message. A new study showed that vaccination after infection produces six times more antibodies than a vaccine alone. This is not to say that one should try to become infected before being vaccinated – immunity to the vaccine alone is more than strong enough to provide protection and the dangers of a fight with COVID-19 far outweigh the benefits. But when my friend and many others who were already infected get the vaccines, they will be well protected.
Natural immunity against infection is simply very doubtful in the face of such a devastating virus. Today’s COVID-19 vaccines offer incredibly strong and consistent protection for the vast majority of people. Therefore, for any eligible person, even those who have already had a SARS-CoV-2 infection, COVID-19 vaccines offer immense benefits.
This article was republished from The Conversation under a Creative Commons license. Read the original article.