“It’s important because people can spread COVID-19 before they know they have it,” said another author. Donald K. MiltonMD, DrPH, Professor of Occupational and Environmental Health at the Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park.
“Early detection can reduce the spread of the disease,” he added.
The motive for the study was the problem that in the early stages of a pandemic, the urgent need to increase testing was associated with a shortage of supplies, especially nasal swabs, which were a common way to collect samples for testing at the time.
To identify COVID-19 patients, the researchers began testing weekly healthy community volunteer saliva samples in May 2020 and continued for the next two years. Of the asymptomatic volunteers who tested positive, Milton and colleagues found that these patients typically develop symptoms a day or two later.
“This made us wonder if saliva was better for infecting asymptomatic patients than traditional nasal swabs,” Milton said.
To answer this question, the researchers used data from a follow-up study of close contacts in people with a confirmed COVID-19 case.
In the study, “we collected saliva and saliva [nasal] take swab samples from the contacts every 2 or 3 days during the quarantine period, “Milton said.
“All samples were tested using a real – time reverse transcription polymerase chain reaction [RT-PCR] detect SARS-CoV-2 and measure the amount of viral RNA in the samples. We then analyze how these results changed in the days before and after the onset of symptoms, ”he added.
In the early stages of infection, saliva was significantly more sensitive than nasal swabs, especially before the onset of symptoms, according to the study. The study found that previous studies had shown that pre-symptomatic infection played a greater role than symptomatic infection. Transmission of SARS-CoV-2.
In the latter case, saliva self-testing avoids the close contact between the patient and the healthcare professional required for nasal sweeping and avoids coughing and sneezing in patients, which spreads virus particles to the sensitive nasal passages as well as discomfort to patients.
“Our research supports the use of saliva in large-scale screening in schools and workplaces as a way to improve screening rates as well as early detection,” Milton said.
“We expect that if rapid saliva tests become available, they could be a big step forward from current nasal swab-based rapid tests,” he concluded.
Source: The Nordic Page