India recorded its first death caused by Omicron in a fully vaccinated person in Rajasthan on the last day of 2021. The 73-year-old man, with co-morbidities, had tested positive on December 15. Preliminary evidence from South Africa and the U.K. suggests that unlike the Delta variant, a majority of people with Omicron, particularly in the fully vaccinated, exhibit only mild disease; hospitalisation is relatively less among the vaccinated. A huge percentage of the population in India was infected when the Delta variant raged last year. Studies from other countries have shown that such people might enjoy the same level or even better protection from severe disease than fully vaccinated people. Hybrid immunity achieved through full vaccination in people who have been previously infected offers the highest level of protection against severe disease, as several studies outside India show. With vaccination picking up speed after the second wave peaked in India, a significant percentage of the fully vaccinated might possess hybrid immunity. Even a single dose of an mRNA vaccine in previously infected people has been found to induce a high level of hybrid immunity. If vaccination coverage with at least a single dose has already crossed 90% in those above 18 years, the rollout of vaccines for adolescents will widen the protective net. But immaterial of the protection conferred, it is too early to draw any conclusions about Omicron’s virulence. For instance, in the U.S., the first Omicron-related death was in an unvaccinated person who was previously infected. The time lag between infection and hospitalisation should be another reason why it is too early to pronounce any verdict on the virulence of the variant in India. Vulnerable populations run a risk of suffering from severe disease despite their vaccination status.
The unprecedented speed at which Omicron is spreading in countries that have high levels of testing, the number of people a single infected person can spread the virus to, and a doubling time of less than three days are a loud warning that things can go out of control soon. Mild symptoms notwithstanding, its higher transmissibility can pose a severe threat to health-care settings as a high number of infections within a short time could lead to more people needing hospital care. Overwhelmed hospitals can make it harder to provide much-needed care, leading to mounting deaths. The situation can become even more challenging when health-care settings suffer from staff shortage caused by increasing infections among health-care workers — as seen in many hospitals across India. India should learn from the hard lessons of the second wave, strictly adhere to COVID-appropriate behaviour and increase vaccination coverage. Getting misled by the mild nature of the disease and throwing caution to the wind will be a dangerous gamble.