As part of a collaboration between the London School of Hygiene & Tropical Medicine, Durham University and the Medical Detection Dogs group, scientists have completed phase 1 of a trial to determine whether, under controlled conditions, dogs could smell and identify Covid-19 infection.
The first results were published in a preprinted study – meaning the work has yet to be peer reviewed or published in a medical journal.
In the Phase 1 trial, working dogs were tasked with detecting Covid-19 on samples of clothing and masks. The researchers examined whether the dogs could distinguish between positive and negative samples for Covid-19.
Dogs have shown a sensitivity rate of around 82% to 94% to detect Covid-19. Chemical analysis of the infection showed a “distinct” odor associated with Covid-19. Researchers are in the process of identifying the exact chemicals behind this scent.
“Dogs could detect Covid with incredible speed and accuracy,” said Logan – “even though a person was asymptomatic. “
The specificity rate, which measured the dogs’ ability to tell if someone did not have Covid-19, ranged from around 76% to 92%.
Study authors say a PCR test is still the ‘gold standard’ for detecting Covid-19, but suggest dogs could provide a faster and easier way to test for Covid-19 in high traffic areas . Dogs could also deter people from going to high-contact spaces when infected.
“The other thing about dogs is that they would serve as a visual deterrent, so if people knew the dogs were going to be screened at the airport, it’s very likely that people would think twice before traveling. they were infected, ”Logan said.
Still work to do
While the first results look promising, it is probably too early to know whether Covid sniffer dogs could actually be used as a tool to fight the pandemic in the real world.
“This could be compromised by the density of individuals in crowded spaces and by the fact that well-ventilated outdoor spaces, where odors are quickly dispersed, compromise the ability of dogs to detect individuals with low levels of infection.” Lawrence Young, a virologist at Warwick School of Medicine who did not contribute to the study, said in a statement.
Young said the research “shouldn’t be sniffed out,” but more work was needed.
“The big question is, will this approach work in the real world on people rather than sample socks and shirts?” ” he said. “There are variations from dog to dog, especially in specificity, which could lead to an increase in the number of false positives. “
Covid-19 infection and dogs
Covid-19 can infect dogs, which could make these types of programs risky for working dogs themselves, said Mick Bailey, professor of comparative immunology at the University of Bristol Veterinary School, who does not ‘was not affiliated with the research, said in a statement.
“A SARS-CoV-2 infection of dogs has been reported, both asymptomatic and associated with varying levels of disease as in humans, so deliberately using dogs to sniff people’s breath and clothing potentially infected seems a bit of a risk for dogs, let alone their owners, ”he said.
SARS-CoV-2 is the name of the virus that causes Covid-19.
“You would need a way around that, like sniffer dog vaccination. Currently, no SARS-CoV-2 vaccine is authorized for use in dogs, although there is no reason to believe that those approved for humans would not work, but the reported low incidence of ‘infections in dogs would make a Phase 3 trial difficult,’ Bailey said.
The two unaffiliated experts confirmed to CNN that dogs have been shown to detect infections in general, and previous studies have suggested that they can indeed detect a Covid-19 infection. However, the specificity of the detection is a looming question, Bailey said.
“For example, the signature that dogs detect may be a general signature associated with respiratory viruses such as the flu, rather than a specific signature associated with SARS-CoV-2,” he said.
Phase 2 of this study will consist of testing the detection capabilities of dogs on people actually infected with Covid-19, and not just on clothing samples.