India, with the world's largest population and a frontline state in the war against Covid-19, is seeing a steady but significant increase in active cases. On May 27, 2025, the country had 1,010 active cases, with the majority of the cases in Kerala, Maharashtra, Tamil Nadu, and Karnataka. This recent upsurge coincides with the detection of two newly emerging subvariants—NB.1.8.1 and LF.7—both descendants of the Omicron lineage, raising cautious concern among public health experts and virologists.Although numbers are still relatively low compared to previous peaks hence there is no need for panic, the appearance of new mutations and uneven booster uptake have pushed India back into the international Covid-19 spotlight. Here's what the resurgence says, what is currently known about the subvariants, and how it might affect global pandemic preparedness.Also Read: CDC No Longer Recommends COVID Vaccine For Kids And Pregnant Women - What Do Experts Think?India had 257 active cases on May 19. Within about a week, the number had passed 1,000, with Kerala contributing more than 400 of them and Delhi reporting over 100 cases. Maharashtra, which includes Mumbai, Pune, and Thane, remains a Covid hotspot, the Ministry of Health and Family Welfare reports.The recent discovery of new strains, especially NB.1.8.1 in Tamil Nadu and LF.7 in Gujarat, also complicates the epidemiological scenario. The latest such confirmed case, that of a 55-year-old woman from Noida in Uttar Pradesh, is the first for that district in the current surge, underlining the slow but consistent dissemination of the virus across geographies.What Are The New Covid Variants Currently Circulating?The new-found sub-lineages NB.1.8.1 and LF.7 belong to the larger JN.1 Omicron lineage. Although these mutations have not yet been tagged as "Variants of Concern" by the World Health Organization (WHO), they are included in "Variants Under Monitoring"—a label for the mutations that can influence virus traits like transmissibility and potential for immune evasion.Also Read: 11-Year-Old Dies From H5N1 Bird Flu In Cambodia, Country Records 100% Fatality Rate In All Human Bird Flu CasesEarly investigations and genomic monitoring indicate that NB.1.8.1 possesses spike protein mutations like A435S, V445H, and T478I, which may make it more infectious and resistant to earlier immunity. LF.7 has also indicated capacity for partial immune evasion, while it is still premature to conclusively evaluate the clinical severity.Dr. Arup Halder, Consultant Pulmonologist, CMRI Kolkata, provided essential insight, "As of May 2025, India is experiencing a modest but significant surge in COVID-19 cases. Though the majority of cases are still mild with low hospitalization rates, the increase is being fueled by newer sub-lineages of the JN.1 variant, namely LF.7 and NB.1.8, which are known to be highly transmissible and partially immunoevasive." What's Driving the Rise in Covid-19 Cases?A number of factors are driving the increasing trend:Declining Immunity: Naturally, immunity from past infections or vaccination weakens with time, increasing the susceptibility of populations to reinfection. Immunocompromised people and older adults are most vulnerable.Weather and Climate: The advance arrival of monsoon in most Indian states has brought with it rising humidity and unstable temperatures—both conducive to transmission of respiratory viruses like SARS-CoV-2.Improved Testing and Reporting: Maharashtra and Kerala states have had strong genomic surveillance infrastructure, which has helped in the early identification of new variants."Maharashtra's high test positivity rate is also due to its population density, international transit points, and early exposure to previous pandemic waves", Dr. Halder added.Vaccination and Booster StatusIndia has so far given over 2.2 billion Covid-19 vaccine doses. Experts have, however, raised red flags over the patchy uptake of booster shots, particularly among high-risk categories like the elderly and healthcare workers. The bivalent boosters are still available, but variant-specific shots remain unavailable in India."Although new variant-specific vaccines are not yet ready, current bivalent boosters continue to reduce symptomatic infections by 50% and severe disease by as much as 80%," said Dr. Halder. "It is important that high-risk individuals receive a booster dose immediately, continue to mask in crowded areas, and practice basic hygiene measures."Across the world, there is increasing concern over access to vaccines. In America, health officials recently dropped Covid-19 vaccination for healthy kids and expectant mothers from the CDC's vaccination calendar on the grounds of requiring more comprehensive clinical trials. Experts are concerned that such limitations may impact global confidence in vaccines and booster campaign momentum in nations such as India.The WHO is monitoring seven variants under consideration, among which are NB.1.8.1 and LF.7. None have been designated as Variants of Concern, but the agency continues to assess how they're evolving using global genomic data.NB.1.8.1, which has been found in more than 22 countries, has demonstrated a consistent rise in share across the world. This suggests a possible competitive edge over other existing circulating strains—worth watching through genomic surveillance and public health readiness.Should You Be Worried?Though the ongoing Covid-19 wave in India is mild in severity and containable with available healthcare infrastructure, it comes as a timely reminder: the pandemic does not end. The virus still mutates, and any slip in surveillance, booster coverage, or public health messaging can lead to populations being susceptible to future waves.Delhi has already advised the hospitals to make beds available, oxygen supplies, and medicines and vaccine stockpiles. States such as Kerala are taking localized containment measures in order to trace the spread and promote testing in high-risk areas.