Community Transmission

Community Transmission

Subject – Science and Tech

Context – Omicron is now in “community transmission” in India and has become the dominant variant in multiple metros, where new cases have been rising exponentially, an INSACOG bulletin released on Sunday said.

Concept –

4 Stages of COVID-19 transmission according to ICMR

• Stage 1:When the disease is just introduced to a population. In India’s case that is with imported cases – only those with travel history to affected countries tested positive for the infection.
• Stage 2: This is when there is local transmission of the disease – some of those in contact with persons with travel history in turn get infected.
• Stage 3: In this stage, there is community transmission i.e. even those who have had no known contact with an affected person, and haven’t travelled to an affected country start contracting the coronavirus disease.
  • According to the Centre for Disease Control and Prevention (CDC), community spread is when “people have been infected with the virus in an area, including some who are not sure how or where they became infected.”
  • This stage makes it difficult to break the chain of transmission, thereby making the disease harder to contain.
• Stage 4: The fourth stage is when there is a widespread outbreak, leading it to become an epidemic within the population and difficult to contain.

Stages of transmission according to WHO

• The first stage is one where there are no cases.
• The second stage is when there are sporadic cases – one or more, imported or locally detected.
• The third stage is when clusters of cases emerge in a time, geographical location and/or through common exposure.
• And the fourth stage is community transmission, which is defined as “larger outbreaks of local transmission”.