As India registered the highest single-day spike of new COVID-19 infections in nearly eight months, the Centre on Monday said five to 10 per cent of the active cases in the current surge so far needed hospitalisation but the situation is dynamic and may change rapidly, and cautioned states against any "lapses" in their preparedness.

The Centre sounded a note of caution on a day when the country began administering a "precautionary" dose against the viral infection. Around 9.3 lakh healthcare and frontline workers, and 60-plus citizens with comorbidities received their third jab, the Union Health Ministry said.

The Indian Council of Medical Research(ICMR), meanwhile, came out with a new advisory that contacts of confirmed COVID cases do not need to get tested unless identified as "high risk" based on age or comorbidities.

As Defence Minister Rajnath Singh, chief ministers of Bihar and Karnataka--Nitish Kumar and Basavaraj Bommai--joined an increasing number of political leaders who have tested positive for COVID, the Centre said the rise in coronavirus cases in various parts of the country appears to be driven by the Omicron variant as well as by the continued presence of Delta.

According to reports from states, police personnel were also getting infected by the virus in large numbers besides the frontline and healthcare workers. In the national capital, nearly 1,000 Delhi Police personnel, including the Additional Commissioner of Police (Crime Branch), have tested positive for the disease, officials said.

The Centre also asked states to keep a watch on cases under home isolation and in hospitals.

In a letter to states and union territories. Union Health Secretary Rajesh Bhushan said that during the second surge of COVID infections in the country, the percentage of active cases that needed hospital care was in the range of 20-23 per cent.

"In the present surge, five to 10 per cent of active cases needed hospitalisation so far. The situation is dynamic and evolving. Therefore, the need for hospitalisation may also change rapidly."

Citing global data, the INSACOG said that in view of Omicron's explosive spread potential the threat level is still very high globally, especially in regions with low population immunity, as the apparent reduction in severity compared to Delta and other previous outbreaks is mainly because of higher population immunity from previous infections and vaccination.

The Indian SARS-CoV-2 Consortium on Genomics (INSACOG), a grouping of 10 National Laboratories, while giving this assessment in its weekly bulletin of December 27 that was released on Monday said global outbreaks of COVID are increasingly shifting from Delta to Omicron.

According to data updated by the Union Health Ministry at 8 am, the country recorded 1,79,723 new coronavirus infections taking the total tally to 3,57,07,727 including 4,033 cases of the Omicron variant reported across 27 states and union territories so far.

The jump in new cases was the highest in around 227 days. A total of 1,86,364 new infections were reported on May 27 last year.

The number of active cases has increased to 7,23,619, the highest in around 204 days while the death toll climbed to 4,83,936 with 146 fatalities, the data showed. An increase of 1,33,008 cases was recorded in the active caseload in a span of 24 hours, it said.

The daily positivity rate was recorded at 13.29 per cent, while the weekly positivity rate was 7.92 per cent, according to the ministry.

"Let there be no lapse in our preparedness as we battle this surge of the pandemic," Union Health Minister Mansukh Mandaviya said interacting with health ministers, top officials and information commissioners of Maharashtra, Madhya Pradesh, Rajasthan, Gujarat, Goa, Dadra and Nagar Haveli and Daman and Diu.

Mandaviya urged the states to make robust preparation in terms of physical infrastructure and efficiently utilize the approved funds under India's COVID-19 Emergency Response and Health Systems Preparedness Package-Phase-II(ECRP-II).

In his letter, Secretary Bhushan said all states and UTs are advised to keep a daily watch on the situation of the total number of active cases, cases under home isolation, the number of hospitalized cases, cases on oxygen beds, ICU beds and on ventilatory support.

He also suggested engaging retired medical professionals or MBBS students for teleconsultation services and providing skill training of community volunteers in basic care and management at COVID Care Centres.

All district hospitals and medical college hospitals should be used as eSanjeevani teleconsultation hubs, he added.