Which is better – immunity from vaccination or after illness

Against the backdrop of the spread of coronavirus and the emergence of new mutations, scientists decided to decide on the answer to the question: “Which is better – to get sick with the Omicron strain or to be vaccinated?”

There is still too little data on immunity to “omicron” to unambiguously answer this question. According to scientists, it all depends on the variant of SARS-CoV-2 that a person has had, and on when the infection occurred, writes Deutsche Welle.

Before the emergence of the new Omicron strain, researchers assumed that after infection with any variant of SARS-CoV-2, the body develops immunity comparable to that formed after the first dose of the vaccine. In particular, Julian Schulze zur Wiesch, head of the Department of Infectious Diseases at the University Hospital Hamburg-Eppendorf, says so. At the same time, immunity after illness persists for several months, and only after 4-6 begins to weaken.

However, most experts continue to consider vaccination the best way to protect against coronavirus. In October last year, the results of a study by the Centers for Disease Control and Prevention (CDC) in the United States were published. They claimed that unvaccinated adults who had already been diagnosed with the virus three to six months earlier were 5 times more likely to contract covid than vaccinated people who had not previously encountered SARS-CoV-2.

But unfortunately, this study only used data from patients who needed hospitalization. Therefore, these results, the document stressed, cannot be generalized to those infected who had a mild illness at home.

And in August last year, completely opposite results were obtained by Israeli scientists. They found that those who had not previously been ill and received BioNTech/Pfizer vaccinations had a 13 times (!) higher risk of infection compared to those who had not been ill and had not been vaccinated.

The study by Israeli scientists has not yet been peer-reviewed. It is considered the largest on this topic to date: 7,000 patients took part in the study of American scientists, and 30,000 in the work of Israeli scientists.

Julian Schulze zur Wiesch explains that many factors influence the body’s immune response: SARS-CoV-2 variant, time of infection, type of vaccine, availability booster dose and, of course, the general state of immunity. It is likely that after infection with other strains, the body’s defenses will be powerless against Omicron. Age is also of great importance.

For example, in September last year, American scientists conducted a scientific experiment involving older people. As it turned out, in them, vaccination with an mRNA vaccine provides more reliable protection against infection, hospitalization and death from coronavirus than a previous infection. In patients under the age of 65 years, protection after vaccination is approximately at the same level as after a previous infection.

But this study has not yet gone through the peer review process. Moreover, the authors of the scientific work admitted that they had previously received financial support from Pfizer.

In March last year, a study was conducted in Denmark. It was based on data collected at the end of 2020, during the second wave of the pandemic. It showed that among young people who had been ill with covid during the first wave, the level of protection was about 80%. In previously ill patients in the age group of 65 years, the effectiveness of immunity reached only 47%.

The wave of “omicron” has passed recently, so there is no solid data on the quality of immunity yet. Scientists believe that a person who has been infected will not be at risk of re-infection for several months. However, given its high contagiousness, the body needs higher levels of antibodies to prevent infection, emphasizes Schulze zur Wisch. Immunity developed after two vaccinations or infection with one of the previous variants of SARS-CoV-2 may not protect against a new infection.

From the expert’s point of view, the most effective protection is provided by a “mixture of immunities”, for example, the first two vaccinations and booster dose made with different vaccines. This is also evidenced by the data of a study conducted last year in Germany among health care workers.

Other studies show that the best immunity is in those patients who have had coronavirus and received two vaccinations. Scientists have called this phenomenon “hybrid” or “super-immunity.”

As for antibodies, according to some data, after a severe form of the disease, their number increases, according to others, it remains the same. But Schulze zur Wisch recalls that all these conclusions are made without taking into account omicron variant of the coronavirus. For those who have not been infected with this mutation in the past two weeks, a coronavirus vaccine will best help protect themselves from COVID-19 and not become its spreader, the scientist believes.

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