India’s Next Biggest Challenge Would Be Tackling COVID-19 Asymptomatic Cases

COVID-19 Asymptomatic Infections In India – The Next Biggest Challenge

An autorickshaw driver from Belur in Kerala’s Kasargod district was admitted to a hospital after hit by a falling jackfruit on May 25. He tested positive for coronavirus during the routine tests conducted before surgery.

The health ministry on April 20 warned that 80 percent of all coronavirus patients showed mild symptoms or were asymptomatic. The spread of asymptomatic coronavirus cases is a matter of concern in India.

Lav Agarwal, Joint Secretary, Health and Family Welfare, at the daily press briefing, said that 15% of patients turn into severe cases and 5% into critical cases.

Among the total coronavirus tests conducted in India so far, 69% were asymptomatic, and 31% were symptomatic cases, said Raman R. Gangakhedkar, Head of Epidemiology and Communicable Diseases at Indian the ICMR on April 21. This means, on an average, three or four asymptomatic patients were found while contact tracing one positive patient.

Mid-April, the Hindustan Times reported that around 75% of the total cases in Uttar Pradesh, 65% in Maharashtra, 50% in Karnataka, and 75% in Punjab were asymptomatic. The health minister Himanta Biswa Sarma said that nearly 82% of the COVID-19 patients in

Assam were asymptomatic.

A new study has estimated that 28% of the 40,184 people who tested positive for the novel coronavirus in India between January 22 and April 30 were asymptomatic. However, Manoj Murhekar, director of the ICMR’s National Institute of Epidemiology and one of the authors of the study published in the journal Indian Journal of Medical Research (IJMR), said that the proportion of the asymptomatic people could be much more than 28.1%. And this is a cause of concern for India.

The study also found that, compared to those with a severe acute respiratory infection, or those with an international travel history or healthcare workers, the proportion of positive cases was two or three times higher among symptomatic and asymptomatic contacts.

Those aged 50-69 yr had the highest (63.3%) attack rate (number of people exposed who are sick divided by the number of people exposed) per million and was lowest among those under 10 yr (6.1%). And the attack rate was higher among males (41.6) than females (24.3).

ICMR advised the states on Saturday to conduct serosurvey to assess the proportion of COVID-19 asymptomatic individuals exposed to coronavirus infection in India.

Below are a few findings from the report:

How did India conduct testing for the coronavirus?

1. A total of 1,021,518 individuals were tested for SARS-CoV-2 (coronavirus) between January 22 and April 30, 2020, of which 40,184 (3.9 %) tested positive.
2. By the end of April 2020, testing increased to 50,000 individuals per day from about 250 individuals per day in March. Over eight weeks, there was a 200-fold increase in testing.
3. 99% of districts ( 729 out of 736) reported any testing.
4. The testing frequency ranged from 182/ million in Manipur to 2149/million in Delhi.
5. States like Andhra Pradesh (1721 tests/million), Jammu and Kashmir (1417 tests/million), Tamil Nadu (1468 tests/million), Haryana (1308 tests/million), Rajasthan (1329 tests/million), Tripura (1251 tests/million), Maharashtra (1070 tests/million), Gujarat (1133 tests/million),  Karnataka (1011 tests/million), Kerala (814 tests/million), and Himachal Pradesh (889 tests/million) conducted higher than national average tests.

Symptoms, age/gender of the COVID-19 patients

1. Cough and fever were the most commonly reported symptoms (64.5 % and 60% respectively) among the 12,810 cases with reported symptoms at the time of specimen collection.
2. Sore throat and breathlessness were reported by around one-third of the cases.
3. Gastrointestinal symptoms such as nausea, vomiting, abdominal pain, and diarrhea were reported by less than 5 % of cases.
4. The attack rate (per million population) was the highest among those aged 50-59 and 60-69-year-olds (64.9% and 61.8%, respectively) and was lowest among those under 10 yr (6.1 %). While the percent positive among tested was slightly higher among females (4.2 vs. 3.8 %), the attack rate (per million population) was higher among males (41.6 %)

Profiles of those who tested COVID-19 positive in India in the time frame:

1. Symptomatic international travelers: 523 cases (1.3 %).
2. Symptomatic contacts of laboratory-confirmed cases: 4,257 cases (10.6%).
3. Symptomatic healthcare workers in 947 cases (2.4 %).
4. Hospitalized Severe Acute Respiratory Infection (SARI) patients: 4,204 cases (10.5%).
5. Asymptomatic direct and high-risk contacts of the laboratory-confirmed case—family members: 10,160 cases (25.3 %)
6. Asymptomatic healthcare workers in contact with a confirmed case without adequate protection: 1,135 cases (2.8 %).
7. ILI (Influenza-like illness) identified in hot zones: 1,199 cases (3.0 %).

The symptomatic contacts (10.3 %) and SARI patients (6.1 %) had the highest number of positive cases. 25.3 % of the 40,184 cases were asymptomatic family contacts, 10.5% were SARI patients, and 10.6 % were symptomatic contacts.

State-wise trends

1. States like Maharashtra, Delhi, Kerala, Punjab, Tamil Nadu, Haryana, Andhra Pradesh, and Gujarat had the highest proportion of districts reporting positive cases.
2. Maharashtra (10.6 %), Madhya Pradesh (6.1 %), Delhi (7.8 %), Gujarat (6.3 %), and West Bengal (5.8 %) had the highest test positivity.

A serosurvey has been advised by ICMR for states to identify asymptomatic people exposed to COVID-19 infection in India. A serosurvey is conducted to know who has been infected in the past and has now recovered by testing blood serum of a group of individuals for the presence of antibodies against that infection. This random test will be conducted in people from 70 districts.

The Indian Council of Medical Research (ICMR) said appropriate public health interventions could be planned depending upon the level of seroprevalence of infection and implemented for prevention and control of the disease.

Blood serum samples of vulnerable or high-risk populations like frontline workers, health care workers, individuals in containment zones, police personnel, and immune-compromised individuals, will be tested for COVID-19 antibodies.

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