New Delhi: An estimated 10.76 per cent of the population in Kerala has already been exposed to SARS-CoV-2 and have developed antibodies, results of a sero survey conducted last month show.
The survey said police personnel were most exposed to the virus, with 15.3 per cent of them having developed antibodies.
The survey shows that the state, which was once hailed for its Covid containment strategy, missed an estimated 27 lakh infections — it has managed to detect just one in four infections.
Kerala has a population of 3.46 crore.
“The proportion of unidentified cases is much less in Kerala as compared to the national average. Kerala might have identified 1 out of 4 actual cases whereas the country as a whole might have identified and reported only 1 out of 30 actual cases. This shows the effort the state of Kerala is taking to identify the cases and declare the number transparently in public domain,” stated the survey conducted by the state health department.
Serological surveys estimate the population-level exposure to an infection by looking at the presence of antibodies in the blood rather than the actual pathogen itself.
The sero survey in Kerala was conducted from 17-28 February in all 14 districts. A total of 12,982 samples were collected from the adult population across the districts. Samples were also collected from frontline and healthcare workers to separately estimate the prevalence of the disease in these groups.
On 28 February, Kerala had reported a total of 10,59,404 cases of Covid-19. Going by the findings of the survey, the actual number of people in the state that had till then been exposed to the virus was in the range of 37 lakh.
The ICMR and the central government had conducted three rounds of sero survey in Kerala during the months of May-June 2020, August-September 2020 and December 2020, and found a seroprevalence of 0.3 per cent, 0.8 per cent and 11.6 per cent, respectively.
Large variations among districts
Alappuzha, Kozhikode and Malappuram were among the top three districts with the highest seropositivity of 15.04 per cent, 13.33 per cent and13.03 per cent, respectively.
At the bottom were Idukki with 5.96 per cent, Wayanad with 6.23 per cent and Ernakulam with 8.13 per cent seropositivity.
Kasaragod, once hailed as a ‘model’ for Covid control, was found to have 10.8 per cent seropositivity.
Kerala’s current Covid tally stands at 11,07,453, with 4,565 deaths. Its case fatality rate is 0.41 per cent — almost a whole percentage point less than the national average of 1.37 per cent.
Among various age groups, those aged between 41 and 50 years were found to have the highest positivity of 11.8 per cent, followed by 11.3 per cent in people aged between 51 and 60 years.
Seroprevalence in females was found to be marginally higher — 10.8 per cent, compared to 10.7 per cent in males.
People from BPL categories were found to have a seropositivity of 11.6 per cent compared to 10.1 per cent in other categories.
The seropositivity among healthcare workers in Kerala was 10.5 per cent. This included all levels of healthcare and categories of healthcare providers.
A total of 12 per cent frontline workers were found to be seropositive, stated the survey.
‘Open up vaccinations’
The surveyors that included personnel from reputed hospitals across the state recommended that given the high percentage of people still unexposed to the virus, vaccinations need to be opened up for all adults.
“Escalate the Covid-19 vaccination coverage in the state at the earliest to achieve a faster rate of population immunity. Vaccination for the 18-60 year population is justified along with vaccinating the priority groups in the state,” read the recommendations from the surveyors.
“Continue the Covid-19 appropriate behaviour in the population without complacency. Reverse quarantine of elderly population needs to go with the same vigour to safeguard them against the pandemic,” the recommendation read.
(Edited by Debalina Dey)