Thiruvananthapuram: A sero-survey conducted by the Health Department indicated that three-fourth of the State population had been exposed to SARS-CoV-2, the COVID-19-causing virus.
The survey found that 70.01 per cent of those unvaccinated have developed antibodies, meaning they had been exposed to the virus. According to official statistics, as many as 48.88 lakh people in Kerala had caught the infection.
The Health Department conducted antibody tests on 847 adults, of which 593 were seropositive. Those who had been exposed to the virus, either through vaccination or contracting the disease, have been considered as seropositive.
The study also found that five per cent of those who had earlier contracted the disease lacked enough antibodies against the virus. The finding indicated that they had lost the immunity some days after getting cured.
The antibodies were found in 95.55 per cent of those who had been infected and 81.7 per cent others who had not contracted the disease.
The Health Department also found 89.92 per cent of those totally vaccinated to be seropositive. The absence of antibodies in the remaining people pointed at the need for booster dose after a stipulated timeframe.
The seropositivity or seroprevalence rate among the partially vaccinated was 81.7 per cent. Among the primary contacts of COVID-19 patients, the presence of the virus was not confirmed in 88.02 per cent.
The survey also revealed vast differences in seroprevalence rate between districts. While Pathanamthitta reported the highest seropositivity rate of 92.35 per cent, Wayanad had the lowest at 70.76 per cent. Virologists termed the vast difference in seropositivity rate between districts 'uncommon'.
The presence of antibodies were found in 82.6 per cent of adults and 40.2 per cent children. Seropositivity rate was highest, 85.78 per cent, among those in the 45-50 age group, while the rate was 85.78 per cent in the 60.74 age group. Meanwhile, the seroprevalence was 77.24 per cent among those aged 75 and above, who were administered the vaccine in the initial phase.
The survey did not find much difference in seroprevalence between male (82.77%) and females (82.47%). Among the above poverty line category, 83.53 per cent had the antibodies, while it was 81.51 per cent among the below poverty line section.
An urban-rural divide was also not found in the survey. As many as 81.75 per cent were found seropositive in corporation areas, while the seropositive rate was 83.44 per cent and 82.15 per cent in municipality and panchayat limits, respectively.
