Now, it’s important to know that while the Delta variant can break down defences and lower vaccine efficacy rates, they are still protective. However, the vaccines that we do have are also different from each other, meaning that the chances of severe infection, complete COVID protection can greatly differ as well.
Interestingly, this has been increasingly seen through amongst many serosurveys and clinical evidence available globally. From traditional viral vector, adenovirus to mRNA vaccine builds, different vaccines have been seen to lose their efficacy rates against the Delta variant and thus, be less or more capable of leading to breakthrough infections. While we may not have complete evidence available yet, recent studies have been able to point to some data about the same:
As per clinical research based out of the USA, currently battling a surge caused by the Delta variant, there was a higher likelihood of contracting COVID-19 amongst beneficiaries who received the Johnson and Johnson Jannsen vaccine (0.59%), followed by Pfizer (0.04%) and Moderna (0.07%). While the Jannsen vaccine is an adenovirus vector vaccine, both Moderna and Pfizer are mRNA vaccines. mRNA vaccines are said to be built using a novel technology that works well in preventing risks and also works more effectively against variants, as per some experts.
Similar revelations have also been observed through serosurveys conducted in India post the second wave. While India is currently seeing the administration of Covaxin and Covishield (both vaccines made through relatively similar traditional vaccine development platforms), some studies have shown that Covishield (Astrazeneca) vaccine was capable of reducing breakthrough cases by a whopping 93% and similarly low rates observed with the administration of Covishield.
Separate studies led by the ICMR have also pointed out that of the two, Covishield is said to mount high effective immunity for recovered COVID-19 patients who have received two doses.
