Large Proportion Of Population Susceptible To COVID-19, Infection Can Spread: ICMR

The Indian Council of Medical Research (ICMR) on Thursday said that large proportion of the population is susceptible to COVID-19 and infection can spread. However, India has not reached the community transmission phase. The ICRM said this on the basis of sero-surveillance to monitor the trend of SARS-CoV-2 infection transmission.

Here’s all you need to know about the survey:

What is serological survey?

Blood samples collected from general population and tested for IgG antibodies
If a person is IgG positive, it means they were infected with SARS-CoV-2 in the past

Serosurveys are expected to answer the following questions

What percentage of the general population has been infected by the virus?
Who are at higher risk of getting infection?
Which are the areas where containment efforts need to be strengthened?

Serosurvey for COVID

ICMR conducted the first serosurvey in May 2020
In collaboration with state health departments, NCDC, and WHO India

Serosurvey had 2 parts

PART I: Estimate fraction of population who has been infected with SARSCoV-2 in general population (COMPLETED)
PART II: Estimate fraction of population who has been infected with SARSCoV-2 in containment zones of hotspot cities (ONGOING)

Data and blood sample collection

Data collection
Socio-demographic details
History of respiratory symptoms
Written informed consent and ethics clearance
Blood sample collection
3-5 ml of blood sample
Laboratory investigations
Sera tested for IgG antibodies, infection using COVID KAVACH ELISA

PART I: Population based serosurvey in districts

Districts into four groups based on number of reported COVID-19 cases (incidence)
Zero cases
Low incidence
Medium incidence
High incidence
Selected minimum 15 districts from each group
400 individuals from each district
Selected 10 villages/urban wards randomly
From each village/ward, enrolled 40 adults
Only one adult enrolled from each household

Results

0.73% of the population in these districts had evidence of past exposure to SARSCoV-2
Lockdown/containment has been successful in keeping it low & preventing rapid spread
However, it means that a large proportion of the population is still susceptible
Risk is higher in Urban (1.09); Urban Slums (1.89) times higher than rural areas
Infection fatality rate is very low 0.08%
Infection in containment zones were found to be high with significant variations (still ongoing)

Conclusion: Way forward…

Since, large proportion of the population is susceptible and infection can spread
Non Pharmacological Interventions such as physical distancing, use of face mask/cover, hand hygiene, cough etiquette must be followed strictly
Urban slums highly vulnerable for the spread of infection
Local lockdown measures need to continue as already advised by GOI
High risk groups: Elderly, chronic morbidities, pregnant women & children less 10 years of age need to be protected
Efforts to limit the scale and spread of the disease will have to be continued by strong implementation of containment strategies by the states
The states cannot lower their guard & need to keep on implementing effective surveillance and containment strategies