FAQ: What is Community Transmission? Has India Entered That Stage?

After eight months into the pandemic, Indian government has admitted to community transmission of virus.

Image used for representation.

(Photo: PTI)

Almost eight months into the coronavirus pandemic, the Centre on Sunday, 18 October, admitted for the first time that there is community transmission in certain parts of the country.

However, experts in the field of public health and epidemiology claim that India was well into the community transmission stage since June.

What exactly is community transmission? Is it important for India to declare whether it is in this stage? Here’s all we know about community transmission.

What is community transmission?

To put it simply, community transmission is when one is unable to trace the source of infection back to the carrier. For example, Person A has COVID-19 and the authorities are unable to trace the contact/source through which he/she got the infection. When this happens repeatedly, for a number of cases, then it is said that the infection is in community transmission stage.

The World Health Organisation (WHO) describes community transmission as “evidenced by the inability to relate confirmed cases through chains of transmission for a large number of cases, or by increasing positive tests through sentinel samples (routine systematic testing of respiratory samples from established laboratories)”.

Community spread is said to be the third stage of the pandemic.

Has India reached the community transmission stage?

Union Health Minister Harsh Vardhan on 18 October, responding to a question on community transmission in West Bengal, said that it is expected to be limited to certain states.

This is the first time the Centre is responding in affirmative to a question on community transmission.

"In different pockets across various states, including West Bengal, community transmission is expected to occur, especially in dense areas. However, this is not happening across the country. It is limited to certain districts in limited states," Vardhan said.

What was said about community transmission earlier?

Delhi Health Minister Satyendar Jain, on 9 June, said the source of novel coronavirus infection in 50 percent of the cases in the national capital was unknown. However, he added that it was up to the Centre to declare whether the city had entered the community transmission phase or not.

Two days after Jain’s statement, on 11 June, Indian Council of Medical Research Director-General Balram Bhargava, in a press briefing, maintained that there is no community transmission of COVID-19 in India.

“India is such a large country and prevalence is very low. India is not in community transmission,” he said.

Bhargava cited India’s first sero-survey to monitor the trend of coronavirus infection transmission, which found that only 0.73 percent of the 26,400 people surveyed from about 65 districts were exposed to coronavirus.

Since then the government has categorically denied community transmission at every stage.

But, what do experts have to say about this?

The Indian Public Health Association, Indian Association of Preventive and Social Medicine, and Indian Association of Epidemiologists released a statement, in the last week of May, saying, “It is unrealistic to expect that COVID-19 pandemic can be eliminated at this stage given that community transmission is already well-established across large sections or sub-populations in the country.”

Echoing the statement, President of Public Health Foundation of India President Dr K Srinath Reddy told The Quint that India cannot be “shy” of facing community transmission.

“We should not fight shy as a nation of facing the prospect of community transmission. Every country has gone through, at some level or other, some form of community transmission. The virus is going to stay with us. It is not in a permanent lockdown – neither is it imprisoned nor exorcised from our community or the planet. We have to make sure the transmission continues to be very slow so we do not have too many people suffering serious consequences.”

Dr Srinath Reddy

He was of the opinion that India “must recognise” community transmission and move on.

Why was the Indian government hesitant to declare community transmission?

Public health expert Dr Mathew Varghese, speaking to The Quint, said that one reason the government could be denying community spread is because in India almost 60 percent of those infected are “asymptomatic”.

Virologist Dr Jacob John told the BBC that only about 0.3 or 0.4 percent of India’s population have been tested.

“In my view, there are two countries in India right now – the four million, or 0.4 percent, tested and the rest. So in a way, the government is saying that 99.6 percent of the country is uninfected – which means the prevalence of infection is very low. And because of such a low rate, there is no community transmission,” he told BBC.

What is the stage after community transmission? How does the pandemic progress?

The first stage of a disease or infection is when it becomes a pandemic – when cases are reported in countries it did not originate in. In the second stage, there is local transmission – this is when one can trace the source of the infection, passing a chain of people.

The third stage is that of community transmission.

Following a prolonged period of third stage (which would vary from country to country), the pandemic becomes an endemic.

An endemic is a disease or condition that is regularly found among particular people in a certain area. The WHO said that the COVID-19 virus may never go away, and like with other endemic viruses, we may just have to live with it, even if there is a vaccine is developed or a cure is found.

(With inputs from BBC)