• There is a new way to collect samples, where one simply spits into a container.
• But Kenyan experts explain why the long nasal swabs, though a little uncomfortable, may be here to stay.
Sample collection for Covid-19 tests is relatively easy and takes less than 15 seconds. But that experience may leave a lasting memory.
Currently, it involves the use of a six-inch (half of the average school ruler) long swab, which is inserted into the nose and rotated several times.
The swabbing might be repeated on the other side of the nose to make sure enough material is collected. Some people cringe, and cough after the swab, but the majority say it is not painful, only uncomfortable.
"I felt like someone was stabbing my brain," one woman in Kawangware told the Star.
Another said she felt like she was breathing in water. Kenya has so far recorded 621 cases of Covid-19.
The current sample collection method, alongside the now abolished patient-pays treatment and quarantine system, has been blamed for the low uptake of testing in Kenya. Besides tedious collection, nasal swabs could expose healthcare workers to infected people because of the need to have close contact during the sample collection.
But now there is a new method, where one simply spits saliva into a container to give a sample for test. Could this shore up the numbers of people willing to be tested?
By Friday, only 29,430 Kenyans had been tested, according to the Ministry of Health. Health CAS Rashid Aman said the turnout for free testing in Kawangware and Eastleigh remained disappointingly low.
"The willingness of the people to be tested is low," he said.
"The Ministry of Health is encouraging Kenyans in the target areas to come and get tested. Experience has shown that countries that have managed to flatten their infection curve quickly have heavily relied on targeted testing. The test will be conducted free of charge.”
The new saliva-based tests have minimally been approved in the United States and remain unavailable in Kenya.
Globally, however, the long nasal swabs remain the gold standard for collecting samples.
In his verdict, the head of the Lancet Laboratories Kenya, Dr Ahmed Kalebi, says the long nasal swabs remain the most reliable way to collect samples.
"Saliva testing is an option but we don’t recommend it as it can have a low yield in persons with the SARS-COV-2 infection leading to a false negative," he says.
"This is because saliva can be variably copious and cause a dilution effect. Saliva amount and content also varies greatly among individuals and even in the same individual depending on gustatory stimulations."
Kalebi explains mucosal swab from the lining of the back of the nose (nasopharyngeal NP swab) or back of the throat (oropharyngeal OP swab) is better because you collect cellular material directly from the mucosal lining where the virus multiplies.
"Sputum is also an option but like saliva, it is fraught with possible lack of adequate material," he told the Star.
Prof Rodney Adam, professor of infectious diseases and microbiology at the Aga Khan University Hospital in Nairobi, also prefers the nasal swabs.
"The saliva test is not a different test but it's the collection of the specimen that's different. The nasopharyngeal swab is more accurate because of the concentration of the virus," he said.
Rutgers University saliva kit was the first to be granted emergency use authorisation by the US's Food and Drug Administration on April 14.
"It means we no longer have to put health care professionals at risk of infection by performing nasopharyngeal or oropharyngeal collections," said Prof Andrew Brooks, chief operating officer and director of technology development at Rutgers, in a statement.
Currently, there's no adequate information to determine accuracy, but some researchers think saliva tests could be as accurate as nasal swabs.
However, on April 22, researchers at Yale University released a study showing saliva is more sensitive for Covid-19 patients than nasopharyngeal swabs.
Collection of Nasopharyngeal specimen with the Swab Technique. H1N1 Influenza A Disease; Information for Health Professionals from the New England Journal of Medicine.
The study notes saliva collection is minimally invasive and can reliably be self-administered.
"Taken together, our findings demonstrate that saliva is a viable and more sensitive alternative to nasopharyngeal swabs and could enable at-home self-administered sample collection for accurate large-scale SARS-CoV-2 testing," says the study, expected to be published in the BMJ.
The study has not been subject to peer review, hence cannot be used to guide clinical practice.
Some 34 health workers have tested positive for the virus since March 13, according to the Ministry of Health.
Acting director-general of health Patrick Amoth said some of the workers contracted the virus away from work. He added that healthcare workers constitute about 5.5 per cent of the cases confirmed in the country.
(Edited by F'Orieny)