People with laboratory-confirmed SARS-CoV-2 on the rear wall of the nasopharynx, but without clinical symptoms COVID-19, have weak immune response against the virus. As noted in the article, published in Nature Medicine, the elimination of the virus from the body asymptomatic patients on average took 5 days longer than in patients with clinical manifestations COVID-19.
Asymptomatic carriage of the virus SARS-CoV-2 occupies a special position in the epidemiological characteristics COVID-19. According to some studies, up to 80 percent of patients find the virus have no symptoms. While other work has shown that asymptomatic carriers of the virus SARS-CoV-2 with high probability not pass it on to other people.
A study conducted by a group of Chinese scientists under the leadership of Chuan-Blue Moon (Quan-Xin Long) from the Medical University of Chongqing, has affected 37 patients with confirmed using diagnostic PCR the presence of SARS-CoV-2 in an organism without clinical manifestations COVID-19 (fever, dry cough or shortness of breath) for 14 days. The study group consisted of patients aged from 8 to 75 years (mean age 41 years). Upon receipt of the 37 asymptomatic patients, three showed a decrease in the number of lymphocytes in the blood, and one — reduced platelets. Six people had elevated levels of alanine aminotransferase (an enzyme that indicates liver damage), and eleven patients were elevated levels of C-reactive protein biochemical marker of inflammation.
Computed tomography of the chest at admission of patients to the symptom of “matte glass” found in 11 asymptomatic carriers (29.7%), and ten patients were observed patchy shadows or diffuse lesions of lung tissue (27,0 per cent). Such characteristic x-ray findings, limited to one lung, was detected in 14 patients (66.7%), while bilateral involvement was observed in 7 patients (33.3%). In 16 patients (43.2%) there were no changes on CT images was found.
Compared with the figures of the polymerase chain reaction 37 patients without symptoms COVID-19 and 37 patients with symptoms of coronavirus infection threshold number of cycle ORF1b RNA were similar (p = 0,336). However, the duration of elimination of the virus (the interval from the first to the last positive smear from nasopharynx) in asymptomatic patients was 19 days versus 14 days in people with symptoms of coronavirus pneumonia.