* More than 90% who showed evidence of antibodies to Covid-19 in the first phase of study, retained it after three months of follow-up
More than 90% of individuals who showed evidence of antibodies to Covid-19 in the first phase of a Primary Health Care Corporation (PHCC) study, retained it after three months of follow-up, Qatar News Agency said in a report on Wednesday.
The PHCC has conducted the study to estimate the extent of the spread of the Covid-19 pandemic using the molecular test (PCR) in addition to blood samples to determine the level of immunity.
The first phase of the survey was carried out at the end of July 2020. The prevalence rate based on antibody and molecular tests among the registered population at PHCC was estimated at 14.6%.
This rate was the lowest among children between the ages of 10 and 17 years (9.7%), and the highest among the elderly (19.8%) aging 60 years and over. The percentage of infection was higher in males compared to females with a great variation according to nationality and municipalities.
The second phase of the study was carried out by the end of October 2020. The individuals who participated in the first phase of the study were invited to retest the antibodies in addition to the molecular test by nose and throat swabs.
The results showed that a total of 943 out of 2,044 people who participated in the first phase of the study completed the second phase successfully. One of the important motivations for implementing the second phase of the study was the conflicting global evidence indicating that the concentration of antibodies in the blood diminishes over time after infection. The results also showed that the antibody test was able to detect twice the number of infected cases discovered by the PCR test alone.
The total prevalence of the pandemic in Qatar within eight months among the primary health care community was 19.1%.
Nearly third of the participants who were positive in the antibody test in the first phase showed a decrease in the concentration of antibodies, while only 8.8% of the participants showed no evidence of retaining the antibodies to the disease.
Director of the Clinical Research Department at PHCC, Dr Hamda Qutbah, said it is reassuring that more than 90% of the individuals who showed evidence of antibodies to the disease in the first phase retained it after three months of follow-up.
The Clinical Research Department is participating in many other studies related to the Covid-19 pandemic, such as the study of antibodies to the disease among healthcare workers, which sheds light on the relationship between the disease and the risk of exposure to it.
