Early detection of Covid variants remains in focus of Centre’s plan

Early detection of new variants of the coronavirus and the containment of infections caused by those variants are among surveillance measures the Centre has decided to focus on amid a surge in cases globally, according to officials aware of the developments.

Last month, the Union health ministry sounded an alert, tightened Covid guidelines and asked states and Union Territories to prepare for any eventuality amid a surge in infections in several nations, especially China.

At least four cases of Omicron sub-variant BF.7 (since July last year), which is currently driving the surge in China, have been reported in India so far. Experts agreed that as long as there is no sign of a new variant, there is no reason to worry.

“So far, the sub-variants in circulation belong largely to the Omicron family (the relatively mild variant), which is why there is no need to panic, as we are an Omicron-infected community with a significant population covered under the Covid immunisation programme,” a senior central government official said, asking not to be named.

“The focus of surveillance measures is going to be on early tracking of new variants and clustering as a result of those new variants,” the official added.

ALSO READ: How 2022 became a turning point in Covid-19 outbreak

The Centre recently issued a set of revised Covid guidelines, with a focus on early detection of cases, isolation, testing and timely management of suspected and confirmed cases. It also stressed the need to detect and contain outbreaks of new Sars-CoV-2 variants and monitoring the trends of existing ones.

The government said its long-term vision is to fully integrate Covid-19 surveillance within the existing Integrated Disease Surveillance Programme (IDSP) that tracks all kinds of outbreaks in the country.

According to the official cited above, all state and district surveillance officers will be involved with the surveillance work in coordination with relevant stakeholders.

As part of surveillance measures, all international passengers arriving in the country will be monitored to detect the entry of the virus and its variants from other countries. The government will also conduct random 2% samples from each flight for RT-PCR testing of international passengers, irrespective of their port of departure and will subject all positive specimens to genomic sequencing, the official said.

All those who test positive for the virus will be kept under observation or quarantine as per prevailing guidelines.

The official said that another important aspect is sentinel surveillance comprising two components – health facility-based surveillance and laboratory-based surveillance.

Under health facility-based surveillance, a nationwide network of sentinel facilities will monitor influenza-like-illnesses (ILI) and severe acute respiratory infections (SARI). All ILI and SARI surveillance data will be reported through IDSP, the second official explained.

ALSO READ: Three from Pune test positive for Covid at airport

All health care facilities will report ILI cases from OPDs(outpatient departments); district surveillance officers will be responsible for analysing data and a proportion (1 in 20) of such cases will be referred to labs for Covid-19 testing through RT-PCR. SARI cases in all district hospitals and selected tertiary hospitals such as AIIMS will be monitored and their samples submitted for RT-PCR testing, the official said.

Laboratory-based surveillance would refer to uploading data on the Indian Council of Medical Research (ICMR) portal. “Data will be analysed for test positivity rates and infection severity,” the official said.

Another aspect will be community-based surveillance that will focus on detection of unusual events in a community, such as large outbreaks and an unusual presentation of cases and mortality.

For whole genomic surveillance, the Centre has asked for continuation and expansion of laboratory networks under INSACOG. The official said that positive samples from large clusters or outbreaks in the community and unusual events will be sent for whole genome sequencing.

Sewage and wastewater surveillance is also crucial in detecting transmission patterns, according to a second government official.

Several studies have demonstrated that any increase in SARS-CoV-2 RNA can be detected in environmental samples several days before detection of Covid-19 through clinical surveillance.

“The Revised Surveillance Strategy for Covid-19 envisages integrating the multiple systems presently existing for a pan-India sewage/wastewater surveillance with the following objectives: provide early warning on the impending local surge of Covid-19; provide an estimate of the virus load in local circulation…” the guidelines said.

The guidelines were revised and issued first in June and kicked in again last month after increase in Covid cases was reported globally.

While sero-surveillance is a useful tool to assess exposure to the virus (and or to vaccination), the guidelines suggest a decision on any such survey needs to be taken on the basis of value it will provide in the future prevailing situation.

Reporting needs to be done on a daily basis, and hospitalised cases will be categorised as those cases requiring oxygen, ICU and ventilator support, among other things, according to the first official.

“These guidelines have already been shared and the states are expected to strictly follow these as early detection is crucial to effectively manage an outbreak,” the official said.