We must get to the root of breakthrough COVID: Experts

Beneficiaries receive Covaxin doses at Nair hospital last week. Pic/Ashish Raje

AMID a growing number of breakthrough COVID infections, many reasons, including variants like Delta and Lambda, waning immunity and immunocompromised people with cancer or AIDS, have come to the fore. With researchers yet to zero in on the exact cause behind fully vaccinated people contracting the virus, health experts say it might be due to diminishing immunity over time post vaccination.

"It has become a matter of serious concern that several people around the world, including India, have been infected despite being fully vaccinated. Besides, many more people have been developing adverse effects [side effects] due to vaccines. A report from the USA of the Vaccine Adverse Event Reporting System which is under the Center for Disease Control revealed that as of August 26, there have been 6,968 deaths due to COVID vaccines," said Dr Wiqar Shaikh, Professor of Medicine at Grant Medical College and JJ Group of hospitals.

Public Health England reported that between February and June, more vaccinated people in England died of COVID than those unvaccinated. "In fact, 163 of 237 people [63.4 per cent] who died due to the Delta variant had been vaccinated. In India, as of June 2021, unreleased government data shows that 26,000 cases of adverse events following COVID vaccines were reported and 488 deaths were linked to post-vaccination complications," he said.

Dr Shaikh said the intriguing aspect is whether vaccines are really effective. "Also, is it that breakthrough infections are by other variants such as Delta, Delta Plus and Lambda? This fact is not being analysed," he said. mid-day had earlier reported that COVID vaccines were developed in a few months, in stark contrast to about 10 years of intensive research done for other vaccines. Also, drugs like remdesivir, hydroxychloroquine, Ivermectin, and plasma therapy that were favoured earlier have now been declared by WHO as having no value in COVID treatment.

Steady rise in numbers

According to Dr Santosh Bansode, HoD, Emergency Medicine, Wockhardt hospitals, there has been a steady growth in the number of breakthrough infections. "Is it because vaccines are not fully protecting people or is it because of new variants? When we get any new fully vaccinated COVID patient we must send his samples for testing to find out which variant.

Vaccine manufacturers can then work on those variants. Now, it is clear that vaccines give a good amount of protection, but still, research should be continued so that we can get vaccines that provide full protection. This also teaches that fully vaccinated people should also follow all COVID protocols and continue taking precautions," said Dr Bansode.

It's becoming more common

Vaccines prevent infection, hospitalisation and death in 60-85 per cent of people, but don't protect everyone. "Breakthrough infections can be caused by Delta and Lamda variants and their subtypes, or waning immunity over a period of time, or some immunocompromised people with cancers or HIV." Dr Subhash Hira, Professor of Global Health at the University of Washington-Seattle and an expert on Infectious Diseases. He said the vaccine-induced effectiveness against Lambda is only 35-40 per cent. "It will be good to see if any Indian study is completed on vaccine breakthrough infections by ICMR and published soon'," he said.

If infected, Dr Hira said, fully vaccinated people can spread fresh strains. "The only solace so far is that these breakthrough infectious have a remarkably low viral load in these individuals. This means they are less infectious to others." He said contacts of such people should wear masks at all times. "Immunocompromised people are now being advised in some countries to take a booster dose after 5-6 months. At some point, when polyvalent booster vaccines are made, there will be different recommendations about booster doses for the general public," he added.

Keep an eye on mutant variants

Dr Ketan Vagholkar, Professor of Surgery at D Y Patil Medical College, said, breakthrough infections have become a global phenomenon, though the risks are much less compared to unvaccinated people. "But their contagious potential continues to be high." He said immunocompromised individuals should take utmost care of themselves. The expert said, "With the increase in the number of fully vaccinated people, the number of breakthrough infections will also rise. Research on breakthrough infections continues in all countries."

60-85
Percentage of fully vaccinated people who are well protected