Coronavirus update: Community spread of Covid-19 in India? Experts, government differ
Ten people hospitalised with acute pneumonia in India have tested positive for the coronavirus disease (Covid-19), according to the Indian Council of Medical Research (ICMR).
Some scientists would consider that community transmission -- the all-important phase 3 of an infectious disease such as Covid-19, where infected people have no history of travel to a Covid-positive country, or direct or indirect contact with an infected person or a carrier.
ICMR’s head of epidemiology and communicable diseases Dr Raman Gangakhedkar admits that there are a few “sporadic instances” such as this, but that “the numbers are not significant enough to establish that there is community transmission because people sometimes don’t recall or don’t give the correct history fearing stigma”.
“Till these numbers are not significantly high, we should not over-interpret it,” he added.
The number of positive cases in India were past 1,000 (1,013) as of 10.30pm Saturday night. On Friday, they rose by over 100 for the first time.
Experts say India’s numbers will continue to remain low because the country’s testing protocol is still very stringent. It is restricted to symptomatic and asymptomatic people with a history of travel to countries hit by the Covid outbreak and contact with infected people, and to health workers caring for Covid-19 patients. While testing has now been expanded to 47 private laboratories (in addition to 113 government ones), the protocol remains the same.
“I don’t know what is stopping the government from doing extensive testing. It’s difficult to speculate on community transmission without data, I think we will know of community transmission only after it has crossed a certain threshold,” said Dr Amit Singh, associate professor, Centre for Infectious Disease Research, Indian Institute of Science, Bengaluru.
The Covid-19 cases with no travel history or contact with a positive case were picked up under the Indian Council of Medical Research (ICMR)’s expanded Covid-19 sentinel surveillance network, under which all patients admitted with severe acute respiratory infection (SARI) admitted in public and private hospitals are tested for the disease, which starts with symptoms of cough and fever, and causes death from acute pneumonia in around 2% of those infected.
But there are gaps even in this, an expert said.
“There has been no solid evidence of community transmission of Covid-19 as yet, but we need to continue monitoring confirmed cases and establish detailed contact tracing to know if we are entering the phase of community transmission. Several states are not implementing the SARI surveillance properly. If all the states implement the SARI surveillance properly, we will know reliability,” said Bengaluru-based Dr Giridhar R Babu, professor and head, lifecourse epidemiology, Public Health Foundation of India.
The expanded testing protocol was announced on March 21 to include all those who are hospitalised with SARI in public and private hospitals to identify Covid-positive cases with no history of travel or contact with a known Covid-19 case, which indicates community transmission. Once community transmission starts, and undiagnosed and often asymptomatic people start seeding outbreaks, it becomes difficult to break the chain of transmission and stop infection.
“Even if one case of unknown etiology is community transmission, and if we can’t trace the source, we are in trouble,” a public health expert said on condition of anonymity.
“At this moment, we have to assume all of us are infected. However, announcing a lockdown means that the government suspected or expected community transmission,” said Dr T Jacob John, retired professor and head of the department of clinical virology at the Christian Medical College, Vellore.
Limiting surveillance to testing SARI patients and people with a travel history or contact with diagnosed cases may exclude unidentified contacts who can potentially seed community transmission, experts said. And widening the testing net will provide more robust data.
The Gujarat model of community surveillance can help identify clusters before they get admitted to hospitals. “The state is tracking data from all 108 EMRI (emergency management and research institute) ambulances, which provide 70% of all medical emergency services in Gujarat and electronically record symptoms of cough, fever and pulse oxygen levels online. A sudden spurt in cases in a location would indicate an outbreak that needs investigation,” said Dr Dileep Mavalankar, director, Indian Institute of Public Health-Gandhinagar.
“The government should have had a system of testing anybody with symptoms at their homes during this lockdown period. If it is cough, fever and breathlessness, it should be treated as Covid-19 unless proved otherwise, so samples should be collected and the person hospitalised and the person’s family should be quarantined. A clinician can understand these symptoms. We could have found a 1,000 or more cases, if it was well tracked,” said Dr John.