Study finds how long Covid causes smell loss for months, even years
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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Trouble ‘Miyas’ everywhere only then they will leave Assam: Himanta Biswa Sarma
Says “Himanta Biswa Sarma, BJP are openly against them, we are saying it openly
New Delhi: Assam Chief Minister Himanta Biswa Sarma on Tuesday said that four to five lakh “Miya voters” would be removed from the electoral rolls in the state once the Special Intensive Revision (SIR) of voter lists is carried out. He also made a series of controversial remarks openly targeting the Miya community, a term commonly used in Assam in a derogatory sense to refer to Bengali-speaking Muslims.
Speaking to reporters on the sidelines of an official programme in Digboi in Tinsukia district, Sarma said it was his responsibility to create difficulties for the Miya community and claimed that both he and the BJP were “directly against Miyas”.
“Four to five lakh Miya votes will have to be deleted in Assam when the SIR happens,” Sarma said, adding that such voters “should ideally not be allowed to vote in Assam, but in Bangladesh”. He asserted that the government was ensuring that they would not be able to vote in the state.
The chief minister was responding to questions about notices issued to thousands of Bengali-speaking Muslims during the claims and objections phase of the ongoing Special Revision (SR) of electoral rolls in Assam. While the Election Commission is conducting SIR exercises in 12 states and Union Territories, Assam is currently undergoing an SR, which is usually meant for routine updates.
Calling the current SR “preliminary”, Sarma said that a full-fledged SIR in Assam would lead to large-scale deletion of Miya voters. He said he was unconcerned about criticism from opposition parties over the issue.
“Let the Congress abuse me as much as they want. My job is to make the Miya people suffer,” Sarma said. He claimed that complaints filed against members of the community were done on his instructions and that he had encouraged BJP workers to keep filing complaints.
“I have told people wherever possible they should fill Form 7 so that they have to run around a little and are troubled,” he said, adding that such actions were meant to send a message that “the Assamese people are still living”.
In remarks that drew further outrage, Sarma urged people to trouble members of the Miya community in everyday life, claiming that “only if they face troubles will they leave Assam”. He also accused the media of sympathising with the community and warned journalists against such coverage.
“So you all should also trouble, and you should not do news that sympathise with them. There will be love jihad in your own house.” He said.
The comments triggered reactions from opposition leaders. Raijor Dal president and MLA Akhil Gogoi said the people of Assam had not elected Sarma to keep one community under constant pressure. Congress leader Aman Wadud accused the chief minister of rendering the Constitution meaningless in the state, saying his remarks showed a complete disregard for constitutional values.
According to the draft electoral rolls published on December 27, Assam currently has 2.51 crore voters. Election officials said 4.78 lakh names were marked as deceased, 5.23 lakh as having shifted, and 53,619 duplicate entries were removed during the revision process. Authorities also claimed that verification had been completed for over 61 lakh households.
On January 25, six opposition parties the Congress, Raijor Dal, Assam Jatiya Parishad, CPI, CPI(M) and CPI(M-L) submitted a memorandum to the state’s chief electoral officer. They alleged widespread legal violations, political interference and selective targeting of genuine voters during the SR exercise, describing it as arbitrary, unlawful and unconstitutional.
