People aged 65 and over have twice the risk of contracting coronavirus again.
Repeated cases of infection with coronavirus infection COVID-19 remain relatively rare, but the risk increases significantly when it comes to people over 65 years old, a large-scale study of Danish scientists showed.
The elderly are less likely to tolerate the disease and more often die from it, so new data must be taken into account in strategies to combat the pandemic, experts emphasize. Correspondent.net tells the details.
Natural protection cannot be relied upon
Cases of re-infection with coronavirus were recorded in 1,362 residents of Ukraine as of March 16, the Public Health Center said.
They noted that we are talking specifically about cases of re-infection, and not about cases of revealing a long course of the disease, which is sometimes mistaken for a new infection.
On March 18, the authoritative medical publication Lancet published the results of a large-scale study conducted in Denmark, which showed that people over 65 who have had COVID-19 are more likely to be re-infected with coronavirus than younger ones.
Denmark has a comprehensive testing program in which PCR testing is performed for everyone, regardless of the presence of symptoms. More than two-thirds of the population, almost four million people, were tested for COVID-19 in 2020.
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Specialists at the State Serum Institute in Denmark divided patients into those who tested positive during the first wave of infections, from March to May, and during the second, from September to October.
They drew attention to cases of re-infection – it turned out that in patients younger than 65 years old who have had COVID-19, the risk of re-infection is reduced by 80 percent, in those who are older – only by 47 percent.
There was no evidence that protection against re-infection had weakened six months after illness. But the full period of protective immunity caused by the infection remains to be determined, the scientists noted.
However, scientists believe that natural protection cannot be relied upon, and vaccination of all population groups is the most reliable measure to ensure protection against COVID-19.
The authors of the study stated that the results obtained underscore the importance of measures to protect older people during a pandemic, first of all, we are talking about distance and priority of their vaccination.
Several studies have shown that coronavirus vaccines have much higher levels of neutralizing antibodies than those found with natural infection. This guarantees the vaccinated people a much longer and better level of protection against COVID-19.
“All these data confirm that in the case of SARS-CoV-2, the hope of protective immunity through natural infections may not materialize and a global vaccination program with highly effective vaccines will be a reliable solution,” Professors Rosemary Boyton and Daniel Altmann of Imperial College London.
In addition to the fact that older people carry COVID-19 more heavily and they have an increased risk of dying from the disease, they are more “effective” distributors, a group of US researchers found out earlier.
It turned out that overweight elderly people exhale on average three times more microdroplets than other categories of people.
The concentration of the virus in the exhaled air also depends on the viral load. However, even with an asymptomatic course of the disease, obesity and age contribute to the release of viral particles.
80 percent of exhaled microdroplets account for 18 percent of people. This corresponds to the traditional distribution for epidemics, where 20 percent of patients account for 80 percent of cases of transmission. Such people are called super-distributors.
The amount of exhaled microdroplets increased as the infection progressed, reaching its highest level a week after infection, the study showed.
Interestingly, as the infection progressed, the viral particles decreased, reaching a size of one micron at the peak of the disease.
Small particles are more likely to be released during breathing, coughing or talking, the researchers note. They can also stay in the air longer, travel farther, and penetrate deeper into the lungs when infected.
The composition and structure of mucus in the respiratory tract depends on the person’s age, diet and lifestyle, scientists explain. Physiological changes affect mucus, which, in turn, affects the amount of microdroplets emitted, including those with viral particles.
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Danish researchers also studied the protection of health care workers from re-infection due to their high risk of exposure to the virus and estimated it to be as high as 81.1 percent. This level is in line with previous studies.
They point out that they “found no difference” in the estimated protection against re-infection between members of different genders, as well as evidence of a decrease in protection over the observed six to seven months. “
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