Vaccination is a powerful tool to break the transmission of COVID-19 and while it is early days yet, the initial indications from Kerala also point towards the fact that new infections are on the way down amongst the vaccinated group.
The percentage of healthcare workers amongst the new cases of COVID-19 reported in the State has been going down, after the vaccination for healthcare workers as a priority group was initiated on January 16.
“It is too early to make sweeping statements but it is a fact that the percentage of healthcare workers amongst the new COVID-19 cases reported in Kerala has gone down by 40% after they began to be vaccinated. If the proportion of healthcare workers amongst those infected was around 1-1.2%, it now constitutes only about 0.6%,” says Arun N.M., an infectious diseases expert, who examined the data.
‘Good protection’
“Remember that most of the health workers have received only one dose (the second dose uptake has been slow and the process is still on). This indicates that even with just one dose, the vaccine (Covishield), offers good protection, as Oxford-AstraZeneca studies demonstrated,” he adds.
The proportion of new infections in the vaccinated and unvaccinated group would give the actual picture but this data is not available in the public domain, Dr. Arun says.
The proportion of healthcare workers who got infected after receiving the first dose/both doses of vaccine and whether there were any hospitalisations amongst the health workers who got infected after vaccination are valuable data that the State should be looking at.
The second dose is being administered after four weeks but the uptake of the second dose of vaccine has been slow amongst healthcare workers mostly because many want to delay it beyond eight weeks, as advised by the WHO.
Inter-dose interval
Increased efficacy with longer inter-dose interval has been clearly demonstrated in the three-nation Phase III trial data of Oxford-AstraZeneca vaccine. Vaccine efficacy was reported to be 76% after a first dose, with protection maintained till the second dose . With an inter-dose interval of 12 weeks or more, vaccine efficacy increased to 82%.
The pre-print of the study in The Lancet said that the vaccine was safe and effective in preventing COVID-19, with no severe cases or hospitalisations, more than 22 days after the first dose.
The fact that new infections have begun to come down amongst those who received a single dose of vaccine in Kerala too should dispel any vaccine hesitancy among the public. However, a public health expert pointed out that the State should sequence viruses affecting vaccinated persons as a matter of priority.
