It doesn’t feel like it at the time, but losing your smell or taste during a Covid-19 infection could be a good thing. Scientists believe it is a sign of a strong immune response.
A study found that Covid patients who suffered anosmia — a loss of smell — or agueisia — a loss of taste — were twice as likely to have antibodies long after an infection.
Previous research has indicated that a strong immune response kills off cells that live in the nose, causing the symptoms.
But it could also be a warning sign of a bad bout of Covid, because these cells tend to be the first infected by the virus.
Loss of taste and smell were more common earlier in the pandemic, when up to three in five sufferers were estimated to have the symptom. But amid vaccination and the spread of new variants, the symptoms have become less common.
It is unclear how relevant the results are now, given none of the participants were vaccinated and the virus has mutated significantly since.
For the study, scientists at Columbia University recruited 306 adults living in northern Manhattan, New York City, who had Covid in the first months of the pandemic.
Their diagnosis was confirmed via PCR tests, antibody tests, or clinical signals of the virus shown on X-rays.
About two-thirds told scientists they suffered from loss of smell or taste when they had a Covid infection. They were invited to the clinic at least two weeks after their infection had cleared for an antibody blood test. Tests were done between April and June 2020.
Antibody test results were available for 266 participants. Of these, 176 tested positive for Covid-fighting antibodies (66 percent) while 90 (34 percent) tested negative.
Antibody levels wane overtime, meaning someone who has been infected with Covid will eventually test negative for the proteins. Results showed 71 percent of those who reported a loss of taste or smell had Covid antibodies.
For comparison, among those who did not report the symptoms, just 57 percent tested positive for the pandemic virus-fighting proteins. The scientists adjusted these results by sex, age and ethnicity for their analysis.
They found that people who lost their sense of taste and smell were about 100 percent more likely to test positive for Covid antibodies than those who did not have the symptoms.
Scientists wrote in the paper: ‘Results from our study suggest that loss of smell and taste during Covid infection are strong predictive factors for a robust immunologic response.
‘Additional research is needed to address the durability of seropositivity among these individuals.’ Previous research suggests loss of taste and smell may be linked to how the body fights off the virus.
There is some evidence that a stronger immune response may lead to more cells responsible for smell and taste being killed off, because these are the first to get infected by the virus.
Covid vaccines have been available in the US since early 2021, and eight-in-ten US adults — or 268million people — have already got two doses.
The scientists warned diagnoses of loss of smell and taste were based entirely on patient recall, with none being tested.
The vast majority of patients were only mildly ill with Covid, in addition, with only five people (1.6 percent) being hospitalized. Participants in the study were 39 years old on average, with the majority being female and from a white background.
- Daily Mail.uk