The State’s decision to widely use RT-PCR diagnostic modality to test select groups in the population to pick up fresh COVID-19 cases from the community is beginning to pay off. Sentinel surveillance sampling done amongst select groups within the general population using RT-PCR tests past five days has thrown up a number of new cases with no clear epidemiological link from different parts of the State, indicating unknown local transmission in the community.
It was on Thursday that the State launched sentinel surveillance sampling in all districts for the pandemic thrice a week, wherein nasopharyngeal swabs from selected groups in the community are collected and tested using RT-PCR. This sample survey is being done separately from the routine testing that the State is doing amongst its quarantined pool.
The number of such new cases — mostly active, asymptomatic cases — that spring up will determine the extent of community transmission of the epidemic.
On Saturday, it was made known that one of the positive cases, who had contracted the disease through “contact” was a health worker in Kollam.
Enquiries revealed that the case was that of an ASHA worker from Chathannoor, who had been tested along with 17 other ASHA workers, as part of the sentinel survey.
Data important
“The data from sentinel sampling is very important and it is totally different from the data of routine PCR sampling done daily and should be accounted for separately. Till now, the State’s surveillance pool consisted of people who had brought the infection from abroad or from other States and their contacts. This situation has totally changed now and the element of uncertainty goes up as we pick up indigenous cases in the community,” a senior epidemiologist told The Hindu .
“Every positive case thrown up in the sentinel survey indicates an area of transmission around that person, which has to be identified, locked down immediately and disease containment activities initiated on a war-footing to limit the spread,” he said.
“In these cases, it is more important to know how the person got the disease than going after the contacts. Intensive surveillance should be initiated in the locality and a bigger sample of those with mild symptoms should be studied. All SARI (Severe Acute Respiratory Illness) cases in clinics and hospitals within a core geographical area and a buffer zone around it should be tested for COVID-19. This should be a systematic process for every positive case thrown up in sentinel survey as part of containment,” he added.
Pneumonia cases
All pneumonia cases reported in private as well as government hospitals frequented by the local people should also be tested to ascertain whether it could be COVID-19, he said.
