Dr Krishna Reddy Nallamalla
After over six months of rising Covid-19 positive cases early last year, India was finally heaving a sigh of relief earlier this year as daily positive cases came down from a high of 100,000 cases in mid-September 2020 to a low of 10,000 cases in early February this year. India could even launch its vaccine diplomacy initiatives in sight of the steadily declining trend. But, as the daily caseload rose six times in the past six weeks to 60,000 cases per day, it seems like the dreaded second wave of the novel coronavirus has become a reality.
What could be the reasons?
As the number of cases steadily declined, Covid appropriate behavior such aswearing a face mask, hand washing, and social distancinggot rapidly diluted. There gradual relaxation of containment measures is also another reason. Public gatherings – social, religious, and political – became more common.
However, these factors alone do not explain the steep rise in cases over the last six weeks. The world has been witnessing the emergence of new variants over the last few months. These variants can be more infectious (for example, the B.1.1.7 that began in UK), more lethal, or evade natural or vaccine induced immunity as seen with the 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 percent 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). It is also possible 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 the virus or antibody isolated earlier should be able to unravel the reasons behind the current spike. The findings of these studies will also guide the public health response to contain the spike.
What mustwe do to contain the spike and prevent the 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 should 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 should be fast tracked without sacrificing the scientific rigor needed. Containment policies should not lead to panic lockdowns. Ongoing research should be well-funded to dynamically generate evidence that can assist key policy decisions.
How do we prepare ourselves to handle the emerging variants?
Over time, 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. The variants are classified as Variants of Concern (VOC) as per the surveillance data. There is also the need to revalidate existing diagnostic tools (virus or its antibody detection) to understand their effectiveness in detecting the new variants.
We must be greatly concerned if the variants are becoming more lethal and evading the natural or vaccine induced immunity. These variants should prompt emergency responses in terms of modification of existing vaccines or development of new vaccines and easingthe regulatory approval process for the new versions of vaccines. The information should also guide the continuation or discontinuation of current vaccines. For example, South Africa suspended the 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 the current wave, and whether the current approved vaccines are effective against the dominant variant. Anecdotal preliminary reports suggest that a smaller number of patients are needing oxygen and ventilator support during the current wave as compared to the first wave.
Take home messages….
- Epidemiological, clinical, and genomic surveillance data of the current wave is urgent and essential to guide the health systems’ response.
- Enforcement of Covid appropriate behavior and standard public health containment methods are vital until the world declares the end of the 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.
Dr Krishna Reddy Nallamalla
Regional Director, South Asia, ACCESS Health International.