According to The Print, approximately 80 percent of Covid-19 patients in India are asymptomatic, an internal analysis by the Integrated Disease Surveillance Programme (IDSP) has concluded after extensive discussions with states.

The last documented estimate on this was 28 percent, published in a study in the Indian Journal of Medical Research (IJMR) in May that looked at cases until 30 April.

Of the symptomatic patients, analysis of all cases until 23 August shows that 25.93 percent reported with fever; 17.18 percent with cough; 7.83 percent with sore throat; and 5.54 percent with breathlessness. However, the largest proportion is of people who reported with other symptoms, such as gastrointestinal problems and loss of smell and taste and body ache.

A senior IDSP official stated, “This is an analysis we have done of all the symptoms that patients have reported with. However, it is important to understand that after many meetings with states, it is now clear that about 80% patients in India are asymptomatic. This is a large number,”.

“We earlier thought that these are presymptomatic people who have been traced and tested during the contact tracing exercise and are essentially presymptomatic, that is they go on to develop symptoms later. However, states have now emphatically told us that these are asymptomatic people not presymptomatic. This is the largest chunk of patients,” added the official.

Until 23^rd of August 2020, India recorded 30.44 lakh Covid cases and 56,706 deaths.

Asymptomatic patients driving the epidemic

A large number of asymptomatic patients are widely recognised as a pool for further spread of the disease. Younger people who are in their 20s, 30s and 40s often tend to be asymptomatic and aredrivers of the disease, the World Health Organization (WHO) said this week. Analysis of data from the top five high burden states in India also bears evidence to this trend.

Initially, 69-80 percent of patients were estimated to be asymptomatic in India. Dr Raman Gangakhedkar, former head of epidemiology, Indian Council of Medical Research (ICMR), had given the 80 percent figure in one of the Covid briefings in April, only to revise it to 69 percent a few days later. However, there was a sharp downward revision in this after the IJMR study of over 40000 patients, in May.

India’s testing strategy banks heavily on whether a person shows symptoms. According to experts, this is so because a person is less likely to test positive unless symptoms are showing. This is provided a person is presymptomatic—which is a transient phase—and not asymptomatic – a condition that can last the duration of the infection.

With such a high incidence of asymptomatic cases, this may need to be revised at some point.

Analysis of signs

The IDSP also analyzed the signs as reported by doctors in their forms.“Symptoms are the complaints that patients come to us for; signs are what doctors discover during their examination,” explained the IDSP official.

This shows that 8.46 percent doctors reported an abnormal lung X-ray or CT scan; 2.78 per cent reported tachypnea or rapid breathing; 1.89 percent were detected with abnormal lung sounds; 0.75 percent had redness of the eyes; 0.66 percent suffered coma; 0.51 percent had seizures and 0.60 percent reported abnormal breath sounds.

The IDSP official explained that while the reporting form is periodically updated, a lot of the newer signs and symptoms have not been included and are in the process of being added. These include dehydration, alteration of acid base balance and abnormal heartbeats. These have been categorized as “other signs” that constitute 83.54 per cent of the reported signs.

Source: The Print