Coronavirus thrives on silent carriers. Beware of loss of smell

By SM.24 Mar, 2020


Novel coronavirus infection became a pandemic because it passed on from one person to many undetected through a chain reaction. Novel coronavirus infected people showed key symptoms of dry cough, fever and loss of breath late or a large number did not show them at all.

They were silent carriers of novel coronavirus infection. It has now emerged that one-third of the total coronavirus patients in China were silent carriers of novel coronavirus infection, the South China Morning Post reported citing some classified data maintained by the Chinese government.

Though data on silent carriers have emerged for the first time, the World Health Organisation (WHO) has long feared this. Its single-point prescription to all affected countries has been: test, test, and test.

It was on this count that many health experts criticised India"s approach in identifying Covid-19 cases and spread in the country. India has tested, except some small random experiments, only those who showed symptoms such as cough, fever and breathlessness.

Thermal scanning has been the most common gateway to Covid-19 testing in India. Experts fear India might have a sizeable number of silent carriers of novel coronavirus infection. Some of them have predicted up to 300 million or 30 crore infections in India by June-July. They have predicted a second wave of novel coronavirus in November-December, when they estimate another up to 800 million or 80 crore people getting infected by the pandemic.

Now, a study based on clinical evidence suggests that anosmia or loss of the sense of smell could be a marker for Covid-19. In a paper released on March 21, the ENT UK - a British association of ear-nose-throat specialists - said it has found evidence for loss of smell among Covid-19 patients.

"There is already good evidence from South Korea, China and Italy that significant numbers of patients with proven COVID-19 infection have developed anosmia/hyposmia [reduced ability to smell]," the ENT UK paper says.

"In Germany it is reported that more than 2 in 3 confirmed cases have anosmia. In South Korea, where testing has been more widespread, 30% of patients testing positive have had anosmia as their major presenting symptom in otherwise mild cases," the study found.

Countries such as Iran, the US, France and Italy - all badly affected by novel coronavirus infection - reported rise in complaints about sudden loss of the sense of smell among patients, who were found to be positive for Covid-19. A large number of these patients did not show regular symptoms of Covid-19.

This study can help India filter Covid-19 patients and silent carriers of novel coronavirus better at a time when almost all states have enforced partial or total lockdown imposing curfew as experts say India has reached the stage where community transmission might take off.

The government and the agencies have maintained till now that except possible four or five sporadic and individual cases, there has been no community transmission of the novel coronavirus infection in the country. In these cases, contact tracing has not yet been conclusive to ascertain the trail of coronavirus infection. The government maintains that the lockdown has been enforced to prevent community transmission of Covid-19 in India.

So, if you have read this report and know someone who has recently complained of sudden loss of ability to smell, advise the person to report the matter to Covid-19 helpline number +91-11-23978046 or 1075.