It has been clear since the beginning of the pandemic: There are people who, despite being infected with Sars-CoV-2, do not feel any signs of illness. How many there could have been for the subvariant omicron is estimated by researchers using current research results.
Researchers have found how many people who were infected with the omicron variant of Sars-CoV-2 did not notice it. The research team led by Sandy Joung and Susan Cheng from Cedar-Sinai Medical Center states that more than half of the study participants were not aware that they were infected with omicron. This variant is associated with less severe symptoms compared to Alpha or Delta. At the same time, it is considered to be more contagious than all other predecessor variants.
For the investigations in the period between autumn 2021 and spring 2022, the data of a total of 6385 people were analyzed. These were patients and employees of the clinic in Los Angeles. In addition, both tests were carried out to determine the antibody against the so-called nucleocapsid protein of the coronavirus. This antibody is only formed in the body of infected people and not in those who have been vaccinated against Covid-19.
The first test was conducted in September 2021, i.e. after the delta wave. The second from mid-December 2021, when Omikron had already become the dominant variant. The researchers then identified the data from 210 study participants who had only formed these antibodies during the omicron wave and were therefore very likely to have been infected with the omicron variant.
Of the 210 subjects aged between 23 and 84, 197 had already been vaccinated against Covid-19. The proportion of women was 65 percent and the average age was 51 years. 92, or 44 percent, of the test persons stated that they were aware of a recent infection with Sars-CoV-2. While 118, or 56 percent, said they were unaware. 12 people, ten percent of the second group, also made it clear that although they noticed any symptoms, they attributed them to another illness, such as a cold, and not to Covid-19. The data also showed that those who were aware of Sars-CoV-2 infection tended to be younger and mostly belonged to the group of clinical workers.
This result cannot only be explained by the differences in general health awareness and health competence between hospital employees and non-employees. They’re more likely to come from mandatory daily testing for medical workers, write the researchers, whose findings were published on the JAMA Network. The research team was not able to determine any difference between the vaccinated and the unvaccinated in this respect.
The current results of the study also support previous findings. The researchers are taking this as an opportunity to once again pay attention to the role of infected people without symptoms in the spread of Sars-CoV-2. The large number of those who were unaware of the infection may have been a factor in the rapid spread of the omicron variant in Los Angeles County. “Our study results show that undiagnosed infections can increase transmission of the virus,” said study lead author Sandy Y. Joung, according to a statement from the clinic. “Low infection awareness likely contributed to the rapid spread of omicron.” Those who have no symptoms or attribute them to another disease are also less careful. “We hope people will read these results and think, ‘I just went to a gathering where someone tested positive’ or ‘I was just starting to feel a little freaked out. Maybe I should get tested quickly’ .” Cheng adds: “The better we understand our own risks, the better we can protect the health of the public and ourselves.”