Washington (PTI): Scientists have uncovered details about the reason behind loss of smell continuing as part of long Covid symptoms, according to a new study.
The reason some people fail to recover their sense of smell after COVID-19 is linked to an ongoing immune assault on olfactory nerve cells and an associated decline in the number of those cells, a team of scientists from Duke University, US, report.
Olfactory nerve cells are associated with our ability to distinguish scents and smells.
The findings, published in the journal Science Translational Medicine, provide an important insight into a vexing problem that has plagued millions who have not fully recovered their sense of smell after COVID-19, the study said.
While focusing on the loss smell, the findings also shed light on the possible underlying causes of other long COVID-19 symptoms - including generalized fatigue, shortness of breath, and brain fog - that might be triggered by similar biological mechanisms.
"One of the first symptoms that has typically been associated with COVID-19 infection is loss of smell," said senior author Bradley Goldstein, Duke University.
"Fortunately, many people who have an altered sense of smell during the acute phase of viral infection will recover smell within the next one to two weeks, but some do not," said Goldstein.
"We need to better understand why this subset of people will go on to have persistent smell loss for months to years after being infected with SARS-CoV-2," said Goldstein.
In the study, Goldstein and colleagues at Duke, Harvard and the University of California-San Diego analyzed olfactory epithelial samples collected from 24 biopsies, including nine patients suffering from long-term smell loss following COVID-19.
This biopsy-based approach revealed widespread infiltration of T-cells engaged in an inflammatory response in the olfactory epithelium, the tissue in the nose where smell nerve cells are located. This unique inflammation process persisted despite the absence of detectable SARS-CoV-2 levels, the study said.
Additionally, the number of olfactory sensory neurons were diminished, possibly due to damage of the delicate tissue from the ongoing inflammation, the study said.
"The findings are striking," said Goldstein. "It's almost resembling a sort of autoimmune-like process in the nose."
Goldstein said learning what sites are damaged and what cell types are involved is a key step toward beginning to design treatments. He said the researchers were encouraged that neurons appeared to maintain some ability to repair even after the long-term immune onslaught.
"We are hopeful that modulating the abnormal immune response or repair processes within the nose of these patients could help to at least partially restore a sense of smell," said Goldstein, noting that this work was currently underway in his lab.
He said the findings from this study could also inform additional research into other long-COVID-19 symptoms that might be undergoing similar inflammatory processes.
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London, Nov 22: A bomb disposal squad deployed as a “precaution” to the South Terminal of Gatwick Airport concluded an investigation into a "security incident" on Friday after making a “suspect package” safe.
The South Terminal of Gatwick Airport, the UK's second busiest airport after Heathrow, which was briefly shut owing to the incident reopened following the incident.
The Gatwick is around 45 km south of London.
Two people detained during the enquiries have since been allowed to continue their journey as the airport was opened.
“Police have concluded their investigation into a report of a suspect package at Gatwick Airport. Officers from the EOD (Explosive Ordnance Disposal) team made the package safe, and the airport has been handed back to its operator,” Sussex Police said in an updated statement.
“Two people detained while enquiries were ongoing have subsequently been allowed to continue their journeys. There will remain an increased police presence in the area to assist with passengers accessing the South Terminal for onward travel,” the statement added.
Earlier on Friday, the incident caused severe disruption at the busy airport’s South Terminal, while the North Terminal of Gatwick Airport remained unaffected.
“Police were called to the South Terminal at Gatwick Airport at 8.20 am on Friday (November 22) following the discovery of a suspected prohibited item in luggage,” a Sussex Police statement said.
“To ensure the safety of the public, staff and other airport users, a security cordon has been put in place whilst the matter is dealt with. As a precaution, an EOD (Explosive Ordnance Disposal) team is being deployed to the airport. This is causing significant disruption and some roads around the South Terminal have been closed. We’d advise the public to avoid the area where possible,” it said.
Footage on social media taken outside the airport showed crowds of frustrated travellers being moved away from the terminal building.
Gatwick said it was working hard to resolve the issue.
“A large part of the South Terminal has been evacuated as a precaution while we continue to investigate a security incident," the airport said in a social media post.
“Passengers will not be able to enter the South Terminal while this is ongoing. The safety and security of our passengers and staff remain our top priority. We are working hard to resolve the issue as quickly as possible.”
Train and bus services that serve the airport were also impacted while the police carried out their inquiries.
In an unrelated incident in south London on Friday morning, the US Embassy area in Nine Elms by the River Thames was the scene of a controlled explosion by Scotland Yard dealing with what they believe may have been a “hoax device”.
“We can confirm the 'loud bang' reported in the area a short time ago was a controlled explosion carried out by officers,” the Metropolitan Police said in a post on X.
“Initial indications are that the item was a hoax device. An investigation will now follow. Some cordons will remain in place for the time being but the majority of the police response will now be stood down,” it added.