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Entering Another Covid Year, R-value Over 1 in big cities


In terms of daily detections of Covid-19 cases, India on the last day of 2021 finds itself in a situation similar to the one in 2020. And yet, the situation in India today is very different from what it was a year ago.

Although the government has not described it as such, there are now unmistakable signs as of January 2022 that India has entered the third wave of the Covid-19 pandemic.


GS-III: Disaster Management

Dimensions of the Article:

  1. With respect to the pandemic, how is the beginning of 2022 different from 2021?
  2. Signal for increasing cases – R-value explained
  3. How is R-value calculated and how accurate is it?

With respect to the pandemic, how is the beginning of 2022 different from 2021?

  • Towards the end of 2020 December, cases were on the downward slope after the peak of the first wave in September 2020. However, now (December 2021) the cases are rising, Covid curbs are in force at many places, and Indians are looking at 2022 with anxiety and trepidation.
  • Another major difference is that: India had not begun vaccinating its population in December 2020, however, India ended December 2021 on a great note by crossing the milestone of 145 crore Covid-19 vaccinations.
  • In the summer of 2021, there was the possibility that central and state governments could have been caught off-guard by the suddenness, magnitude, and ferocity with which the infection surged. However, for the Summer months of 2022, India is entering the surge more than a month after the countries in the West and has had time to plan and prepare an adequate response to prevent not just the loss of lives but also economic disruptions.
  • Since the Omicron variant of the coronavirus, which is driving the latest round of infections, is producing only mild cases, India may have to deal mainly with a surge in cases, not necessarily loss of lives.
  • Also, it is reassuring the No country in which Omicron is currently rampaging, as of January 2022, has seen a significant rise in the Covid death rate.


Signal for increasing cases – R-value explained

  • R-Value, also known as R0-Value, R Factor or number, it is the effective reproductive number of a virus.
  • It is the number of people an infected person will pass on the virus to.
  • For example: If measles – a highly contagious infectious disease – has an R number of 10 in populations without immunity, this means every infected person will spread the virus to 10 others, on average, who will then infect 10 more and so on.
  • During the second wave, when COVID-19 spread was rampant across India, scientists had estimated that the overall R-value in the country to be 1.37 from March 9-April 21. It declined to 1.18 between April 24 and May 1 and further to 1.1 between April 29 and May 7.
  • As of January 2021, Kerala has an R-Value of 1.11.

How is R-value calculated and how accurate is it?

  • It is difficult to capture the moment when a person catches the infection. Almost always, infections are detected with a delay.
  • So, scientists work backwards to collect the data related to the spread of a virus – such as the number of people dying, admitted to hospital or testing positive for the virus over time.
  • This data is used to estimate how easily the virus is spreading.
  • Initially, the R-Value was used to understand whether a population was growing or not within geography. Scientists later deployed the same method to know the viral spread.
  • Some scientists have argued against relying only on R-Value to decide when to impose restrictions, saying R-Values are only an indication of the spread and it has a time lag. The virus could be moving at a faster pace than this modelling would suggest.
  • There are two other ways, they say, that should also be considered in addition to the R-Value. One is the severity of the infection and the other is the number of cases.

Why is R-value of more than 1 dangerous?

Because this indicates that every infected person is spreading the virus to more than one person, resulting in a continuous increase in viral cases.

Authorities all over the world try to bring the value of R to less than one to control the movement of a virus and eventually stop the outbreak.

-Source: Indian Express

April 2024