From March to May 2021, India has seen an increase in COVID-19 cases which has resulted in medical services becoming overburdened. However, the vaccine has played an important role in the whole COVID-19 story. This article presents a study of how efficiently the vaccines in India have performed with regard to the different variants. 

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The Indian variant

While just a tiny percentage of samples have been sequenced, the B.1.617 lineage has been shown to predominate. B.1.617.2 was discovered in India for the first time in December 2020 and quickly became the most frequently reported variation in the country by mid-April 2021. The variation had been found in 43 countries across six continents. There has been a dramatic increase in instances of this variation in the UK, which has been linked to travel to India and community transmission.

Vaccine efficacy towards variants

British researchers discovered that both the Pfizer and AstraZeneca COVID-19 vaccines were effective against symptomatic sickness caused by B.1.617.2, the so-called Indian variety. Two doses of Pfizer's vaccination demonstrated 87.9 per cent efficacy (95 % confidence interval [CI] 78.2 per cent-93.2 per cent) against the variation, whereas two doses of AstraZeneca's vaccine showed 59.8 per cent efficacy (95 per cent CI 28.9 per cent-77.3 per cent), according to Jamie Lopez Bernal, PhD, of Public Health England in London, and colleagues in an online preprint publication.

Vaccine efficacy against B.1.617.2 was equally poor following a single dosage for both vaccinations, at 33%. "To our knowledge, this is the first research to reveal vaccination efficacy against the B.1.617.2 mutation", the scientists said. They employed a case-control study with data on vaccination status up to May 16, 2021, and PCR testing from October 26, 2020, to May 16, 2021. They then identified both the B.1.617.2 and B.1.1.7 variants using whole-genome sequencing or a proxy assay (saying positive or negative for the spike gene target) (the so-called U.K. variant).

The vaccine's effect was defined as the beginning of symptoms 21 days after the first dose and lasting until the second dosage was delivered (one dosage), and 14 days after the second dose (two doses). In all, 12,675 specimens were sequenced, with 11,621 being B.1.1.7 and 1,054 being B.1.617.2.

B.1.617.2 instances included a greater number of women, a greater proportion of "Indian or Indian British" or "other Asian origin" ethnicity, as well as a greater proportion of international travel and more recent cases. For the B.1.1.7 strain, the combined vaccination efficacy was 51.5 per cent. However, efficacy against B.1.1.7 was 93.4 per cent (95 per cent CI 90.4 per cent -95.5 per cent) after two doses of Pfizer vaccine, compared to 66.1 per cent (95 per cent CI 54.0 per cent -75.0 per cent) after two doses of AstraZeneca vaccine.

The decrease in vaccination efficacy appeared to be larger with AstraZeneca's vaccine (OR 1.48, 95 per cent confidence interval [CI] 1.18-1.87) than with Pfizer's vaccine (OR 1.17, 95 per cent CI 0.82-1.67). "These data imply a slight decrease in vaccination efficacy", the scientists said. "However, after two doses, a clear impact of both vaccinations was observed with a high degree of efficiency". The statistics are limited by the fact that this was observational research, which means that unmeasured confounders such as variations in the populations receiving each vaccination are conceivable. Additionally, they emphasised that the limited sensitivity or specificity of PCR testing might have resulted in persons being misclassified as positive or negative.

Final Thoughts

After two doses, a high level of vaccination efficacy against symptomatic illness was observed. This data suggest the maximisation of vaccine uptake with two doses in susceptible populations in the setting of B.1.617.2 circulation.

New data's repercussions for India 

The new findings come from an in-depth assessment of real-world situations. In contrast to a clinical trial, which collects data in the "future" by dividing participants into two groups, vaccinated and unvaccinated and tracking their infection rates to find out the differences in infection rates, real-world research gathers data in the "past". It analyses data to determine if an individual is COVID positive or negative. By combining vaccination information with testing data, it is possible to compare the vaccine efficacy.

The latest study screened 1,054 individuals for the B.1.617.2 strain, 244 of whom had received the AstraZeneca vaccination. The AZ vaccine (two-dose regimen) was 59.8% effective against this variation. Against the B.1.1.7, the efficacy was 66.1 per cent. Confidence intervals that overlap suggest that there is no statistically significant difference between the two figures. A single dosage was determined to be effective at 32.9 per cent. The study does not specify the time period for which this single-dose efficacy is estimated.

The best part is that the two-dose approach works against the new variety. Although this figure cannot be directly compared to the effectiveness reported in the clinical study, the fact that it is identical to the B.1.1.7 variation suggests that the vaccine is effective against several variations.

The effectiveness of a single dosage is critical. As previously stated, strong effectiveness over an extended period of time enables a vaccination programme to expand the interval between two doses and so give protection to a larger population. The success rate of 32.9 per cent indicated in this research looks low in comparison to the 76 per cent shown in the clinical study.

However, the critical metric for public policy is efficacy against serious sickness, since this figure determines the load on hospitals and medical infrastructure. This figure has not been calculated yet but will be critical in determining future policies. One thing we can do to influence public policy is to use our data to evaluate vaccination efficacy in our own population rather than waiting for others to provide it. There is information on almost 180 million vaccination doses that have previously been delivered. The vaccination data and the PCR test data are linked via the Aadhaar unique ID (and potentially further genomic data). When the three data sets are combined, the necessary details on vaccination efficacy should be obtained. Instead of using an overall constant inter-dose interval, additional data such as the detection of "hot spots" might be utilised to adapt vaccination distribution policy locally.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.