Mitigating the third wave requires a focus on DOTS

Synopsis:

India is witnessing a softening of the second wave. Nonetheless, the anticipation of the 3rd wave is quite high. Therefore, it is imperative for India to focus on reducing the reproduction number (R). This in turn calls for focusing on its determinants i.e. DOTS for Mitigating the third wave

Background:

• India witnessed a brutal impact of the second wave of the pandemic in May 2021, with cases crossing the 4 lakh mark in one day.
• The situation has now eased and the number of cases has come down below the 1.5 lakh mark. The second wave appears to be abating due to a reduced reproduction number.

About Reproduction number (R):

• It refers to the average number of new infections arising from one infected individual.
• R greater than 1 implies that infected individuals infect more than one person on average, and we observe increasing cases. When it is less than 1, cases are declining.
• It is dependent on Four Factors, summarised by the acronym DOTS: 
  • Duration a person is infectious 
  • Opportunities for infected individuals to spread the infection to others; 
  • the probability of Transmission of infection if given an opportunity 
  • the average Susceptibility of a population or subpopulation 

What led R to increase earlier this year resulting in a second wave?

• Susceptibility: It was quite high at the start of the year. This is evident from the results from a national seroprevalence survey done in December 2020 and January 2021. They indicate roughly 25% of the population had antibodies to the virus that causes COVID-19.
  • Further, less than 1% of the total population had received two doses of the vaccine till March 2021.
• Opportunity for Transmission: By January 2020, people perceived that they had won the battle over the pandemic. They were eager to get back to life and work. Eventually, this increased the social mixing and the occurrence of large gatherings that might have facilitated a second wave.
• Probability of Transmission: A fall in Covid-19 appropriate behaviour was witnessed in early 2021 like not wearing masks in public, not properly sanitizing oneself etc. Further new variants with higher transmissibility potential emerged.
  • For instance,  B.1.617.2 (the delta variant) is known to possess higher transmissibility potential, twice than the Covid-19 variants circulating in 2020. It has emerged as the dominant variant in India and UK during their second wave.
• Duration of infectiousness: It may have enhanced with the emergence of new variants however more research is needed on this front.

 Read Also :-War against tuberculosis in India: an overview 

Therefore, it is now imperative that we need to focus on DOTS for Mitigating the third wave.

Suggestions for Mitigating the third wave:

• The government must build well-designed seroprevalence surveys to understand how much of the population remains susceptible and where they reside. These should accommodate the complexities of new variants and the occurrence of reinfections.
• The focus should be on increased use of face masks and improved ventilation for reducing the transmission. The country can learn from the Bangladesh model in which the distribution of free masks coupled with community monitors delivered positive results. 
• Temporary solutions like lockdowns and a ban on mass gatherings should be used to focus on slowing the transmission rate.
• The magnitude of the susceptible population can be brought down by substantially increasing the immunisation coverage. Currently, only 3% of the population has received both doses.
• The isolation and quarantining guidelines should be revised periodically as per the changing duration of infectiousness.

Source: The Hindu