As the covid-19 pandemic is emerging in the world, it is getting studied in different parts of the world. We are coming across new information about the virus and its variants. In the recent study conducted in the UK it was found that two doses of vaccine are necessary to build effective immunity against the new coronavirus strains.
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2 dose vaccines for Covid 19
Though there are many waxing brands available in the world for covid-19, companies like johnson and johnson has come with its single dose vaccine. Other companies like Sputnik are in search of a single-dose option.
Apart from Johnson and Johnson majority parts of the world are 2 dose vaccines. Countries like India which depend on astrazeneca vaccine which is a 2 dose vaccine, a very small percentage of population has been fully vaccinated with two doses. Developed countries like the USA are relying on vaccines from Pfizer and M ofoderna which are two dose vaccines. Till date half the population of the USA is fully vaccinated with 2 dose vaccines.
The two dose vaccines available in the USA have above 95% efficacy. But vaccines available in India and the UK supplied by Astrazeneca have efficacy only 70%.
What was the study about?
The PHE study was about the efficacy of a single dose of vaccine against the new coronavirus variants. It was conducted for the different brands and for the different variants currently circulating in the population.
This study examined various 2 dose vaccines against the variance of the coronavirus. It tried to measure the efficacy of a single dose against the two doses of the coronavirus new variants.
Which variants?
Currently the most important variant which was first detected in India and spread to the other part of the world is B1.617.2.
This PHE study examines a frequency of single dose and two doses of vaccines against warriors virus variants that are circulating in the population.
What are the findings?
| Variant | Pfizer vaccine efficacy against symptomatic Covid disease | Astrazeneca vaccine efficacy against symptomatic Covid disease |
| B1.617.2 variant | Single dose 33 percent After 2 dose 88 percent | Single dose 33 percent After 2 doses 60 percent |
| B1.1.7 variant | Single dose 50 percent After 2 dose 93 percent | Single dose 50 percent After 2 doses 60 percent |
From the above data it is clear that both the maximum are only 33% effective against the common variant B1.617.2 after a single dose. These vaccines are 50% effective against the variant B1.1.7.
The efficacy of the Pfizer vaccine after 2 doses sharply increased to 88% and 93%. While the efficacy of astrazeneca vaccine after 2 doses is 60% and 66% against these common variants of the virus.
It is also a point that the Astrazeneca vaccine was given only to elderly people so the efficacy may be low.
What are the take home messages?
The important inference and the message we got from the studies is that majority of the population should get vaccinated with two doses as quickly as possible.
To stop the spread of the virus variants and break the chain of the disease we need stronger immunity in the population. To build a strong immunity we need the maximum effect of the vaccine.
For the best results and optimum immunity two doses of these vaccines are necessary, the single dose is likely to be ineffective.
Countries like India bear the disease burden with these variants is still high and should focus on complete vaccination of the population.
“We expect the vaccines to be even more effective at preventing hospitalization and death,” said Dr. Mary Ramsay, head of immunization at PHE, in a statement. “So it is vital to get both doses to gain maximum protection against all existing and emerging variants.