Research carried out in China on 178 patients suggests that the immune response to Covid-19 may prove to be less strong in people diagnosed positive but who have not shown symptoms relating to the disease.
- The researchers found a drop in the amount of antibodies thought to immunize against the virus by 81.1% in the 37 asymptomatic patients compared to 62.2% in the other participants.
- This suggests that it is important to maintain barrier gestures to avoid a second epidemic wave.
According to a study published in the journal NatureMedicinepeople who have contracted Covid-19, but without developing symptoms, could at the same time present a immune response weaker. To reach these conclusions, scientists from the Chongqing Medical University (China) studied the cases of 178 patients from the district of Wanzhou diagnosed positive for SARS-CoV-2. Among them, about fifteen men and 22 women, aged 41 on average, did not show any symptoms.
The researchers who led the study found that the extraction of viral particles in asymptomatic patients took an average of 19 days, 5 more than other patients who developed clinical signs of the disease (cough, shortness of breath, fatigue etc.).
Eight weeks after patients who took part in the study were discharged from hospital, researchers found a drop in the amount of antibodies believed to immunize against the virus by 81.1% in the 37 asymptomatic patients, compared to 62. .2% among the other participants.
“These data suggest that asymptomatic people had a weaker immune response to SARS-CoV-2 infection. Reduction in IgG and neutralizing antibody levels in the early convalescent phase could have implications for immunity strategy and serological studies”, the scientists wrote.
Short-lived immunity?
In view of these results, the authors of the study insist on the need for broader research and to take into account the potentially short nature of an effective immunity against the virus. They also insist on the importance of maintaining barrier gestures and other preventive measures (social distancing, wearing a mask, hygiene) in order to avoid the occurrence of a second epidemic wave.
“However, this estimate may not be accurate with respect to the proportion of asymptomatic infections in the general population, as asymptomatic infections have been identified among those at high risk of infection (including close contacts and people with travel history to Wuhan) and not among a random sample of people. Therefore, the proportion of asymptomatic infections should be determined by population screening”conclude the researchers.
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