Even as from January 10 in the New Year, the country will launch a booster dose drive for the 'at-risk' individuals - health workers, frontline workers and 60-plus citizens with co-morbidities, the moot point here is will the booster dose give protection against Omicron?
While studies from the world's Omicron hotspot UK to that in India shows that vaccinated individuals were the ones detected with the new mutant, the eye-popping fact here is nearly 3 percent of vaccinated Omicron positives in the country had received booster doses.
As per a study by Union Health Ministry, when 87 of 183 Omicron positive cases are fully vaccinated, 3 of them had even received 3-doses. The Health Ministry analysis shows a whopping 47 percent of new Omicron positives are fully vaccinated, and 3.4 percent of them had received booster doses.
UK Study
A recent study published in bioRxiv revealed that it had been observed in the UK that individuals infected with earlier SARS CoV-2 variants have little protection from Omicron infection.
But the silver lining in the study is Omicron infected individuals who had previous delta infection, and also had been vaccinated, then their blood serum shows a higher quantity of neutralising antibodies (IgA, IgM, IgG).
As per the study, the increased concentration of IgA, IgG and IgM in individuals having hybrid immunity (natural infection + vaccination) shows that Omicron escaping the immunity is quite low.
The study revealed that the neutralization titres for Omicron were boosted 2.7-fold in the case of AstraZeneca (Indian Covishield) and 34.2-fold following the third dose of Pfizer-BioNTech vaccine compared to 28 days following the second dose.
The UK study results show booster dose will give greater protection against Omicron vis-a-vis the double doses.
ICMR Analysis
An ICMR analysis in India (Kolkata) shows that the cell-mediated immunity triggered by both Covaxin and Covishield shots will be 10 months.
Another study done in Kerala reveals that hybrid immunity (delta infection + fully vaccinated) lasts longer and is stronger than only vaccine-induced immunity.
A third study in Chennai finds a good concentration of anti-spike protein antibody and neutralising antibodies even after 6-months in 70 percent of 116 studied individuals.
An analysis of the Union Health Ministry reveals that there is more than a 90 percent chance of reduction in re-infection for 10-months.
The analysis further added that re-infection is very unlikely within 9 months post-natural infection.
Third Wave Time?
A glance at the Union Health Ministry analysis revealed that nearly half of Omicron positives in India are vaccinated. When the clinical symptoms were seen in tandem, then it was found that 70 percent are asymptomatic and 30 percent are symptomatic.
Asymptomatic in a large number of individuals show the impact of either hybrid immunity or the vaccine-induced one.
Since high chances of preventing re-infection have been estimated between 9-10 months, the Omicron peak in India, including Odisha, will come in February-March.
Therefore, the Union Health Ministry had today said, "vaccines are disease-modifying (means reduce the severity and complications), not infection preventive."
The Key Takeaway
In the given epidemiology of the ongoing pandemic, the Centre has asked all states to ensure masking before and after vaccination. Also, all state governments would ensure crowding at public places before or after vaccination to stop mutation and transmission of the lethal virus.