India was heaving a sigh of relief as daily positive cases came down from a high of 100,000 cases a day in mid-September of last year to a low of 10,000 cases a day in early February of this year. India could even launch its vaccine diplomacy looking at the steadily declining trend. As the daily cases rose 6 times in six weeks to 60,000 cases per day, the dreaded second wave has become a reality says Dr Krishna Reddy Nallamalla ; President, InOrder & Regional Director, South Asia, ACCESS Health International.
What could be the reasons?
As the cases steadily declined, Covid appropriate behavior – face mask, hand wash, and social distancing – got rapidly diluted. There has been gradual relaxation of containment measures. Public gatherings – social, religious, and political – became more common. These factors alone do not explain the steep rise in cases over the last six weeks. The world has been witnessing emergence of new variants over the last few months. These variants can be more infectious (B.1.1.7 that began in UK), more lethal, or evade natural or vaccine induced immunity as seen in South African and Brazilian variants. India recently reported a double mutant variant. However, its behavioral pattern is yet to be elucidated. Considering the fact that the recent seroprevalence studies pointed to more than 50% seroconversion in many metros, the spike being seen in these metros may point to a variant that is evading immunity developed following natural infections (asymptomatic or symptomatic). Or it may be that the natural immunity following asymptomatic or mildly symptomatic infections may not last long.
Public health research, viral genomic surveillance data analysis, and study of immunity in people who either had virus or antibody isolated earlier should unravel the reasons behind the current spike. The findings of these studies will also guide public health response to contain the spike.
What should we do to contain the spike and prevent loss of lives and livelihood?
Standard public health measures of test, trace, isolate shall continue until the pandemic is declared to be contained world-wide. People shall not let their guard down in following Covid appropriate behavior of face mask, hand wash, and social distancing. Vaccination should be ramped up without sacrificing the need for rigorous post-vaccination surveillance. New vaccines approval shall be fast tracked without sacrificing the scientific rigor needed. Containment policies shall not lead to panic lockdowns. Ongoing research should be well-funded to dynamically generate evidence to assist in key policy decisions.
How do we handle emerging variants in order to prepare ourselves?
Mutations are to be expected amongst bacteria and viruses as part of their evolution. National level effective surveillance systems track these mutations on an ongoing basis, and not just only during epidemics and pandemics. Epidemiological and clinical surveillance will provide insights into the behavior of these mutant variants in terms of their infectivity, lethality, and immune evasion. There is also need to revalidate existing diagnostic tools (virus or its antibody detection) whether they are effective against the new variants. Once the variants are classified as Variants Of Concern (VOC) as per the surveillance data.
We have to be greatly concerned if the variants are becoming more lethal and evading natural or vaccine induced immunity. These variants should trigger emergency responses in terms of modification of existing vaccines or development of new vaccines and defining regulatory approval process for these new versions of vaccines. The information should also guide on continuation of current vaccines. For example, South Africa suspended Astra-Zeneca vaccine as the evidence of its lower efficacy against the new variant was building up, while UK continued with it as it was found that the vaccine is effective against the new variant found in UK. We are not yet clear in India as to which virus variant is dominant during current wave, and whether the current approved vaccines are effective against the dominant variant. Anecdotal preliminary reports suggest that less number of patients are needing oxygen and ventilator support during the current wave.
Take home messages.
- Epidemiological, clinical, and genomic surveillance data of the current wave is urgent and essential to guide health systems’ response
- Enforcement of Covid appropriate behavior and standard public health containment methods are vital until the world declares the end of Covid-19 pandemic
- There is an urgent need to revalidate the existing diagnostic tests and vaccines against the dominant strain if it happens to be a new variant