Infectionist Pozdnyakov on the opinion of South African scientists on tests for COVID-19: there is no need to change them
Photo: Mikhail Voskresensky / RIA Novosti
The disease with the omicron strain of coronavirus can be detected faster and easier if the swab for the PCR test is taken from saliva, and not from the nasopharynx. The corresponding study by scientists from the University of Cape Town of the Republic of South Africa (South Africa) is published on the MedRxiv portal.
Scientists analyzed tests from 382 patients at a Cape Town hospital between August and December 2021. According to studies, when testing in infected people on the basis of a nasal swab, in 14 percent of cases the omicron strain cannot be detected.
Strain “delta” in saliva was found only in 71 percent of cases, in the nasopharynx its presence was confirmed in 100 percent. With omicron in smears from the nasopharynx, it was found only in 86 percent of cases, and in saliva a new strain was always determined. The publication notes that in Russia, sampling procedures for coronavirus prescribe a swab from the nasopharynx (or oropharynx) and prohibit the collection of saliva.
Based on the results of the study, Izvestia decided to interview companies involved in testing for COVID-19 on whether there will be changes in the process of diagnosing the disease due to the spread of Omicron. Andrey Pozdnyakov, infectious disease specialist, chief physician of the Invitro-Siberia clinical diagnostic laboratory, noted that scientists have different theories about why Omicron is better detected in saliva.
“But for practical healthcare, this is not important. If you need to take saliva, it is even easier than a swab from the nose, so there are no difficulties with the PCR test technique. There is no need to change the tests for a simple reason – PCR determines the presence of SARS-CoV-2 RNA, and not a specific strain. For practical healthcare, this is enough, and epidemiologists need information on a specific strain,” he said.
