The Ministry of Health and Family Welfare reported that over 14,000 people tested positive for COVID-19 after taking one or both doses of the available COVID-19 vaccines in one district of Kerala. While Kerala is already dealing with a high daily COVID-19 case load, news channel NDTV citing a source from the Union Ministry suggested that the southern state may have over 40,000 such cases.
After Kerala's numbers were made public, there was a demand for knowing the actual number of 'breakthrough infections' in the country. Scientifically, those who test positive for a particular infection after receiving a vaccine against the same are classified as breakthrough infections. The health ministry later shared that over 2.6 lakh people in the country have reportedly tested positive after receiving either one or both the doses of Covishield, Covaxin or Sputnik V, the three vaccines that are currently commercially available in the country. Close to 1.17 lakh of them tested positive after one dose, while the remainder were fully vaccinated.
The Indian Council of Medical Research, however, only updated its RT-PCR and rapid antigen test consent form to include questions on the vaccination status of the individual only in April. IndiaSpend even analysed test consent forms to show that several testing labs as well as states were not accounting for vaccination cases and thus, the government may have actually missed on counting several cases of breakthrough infections among health workers and people above the age of 45.
Although the virus transmits and infects even the fully vaccinated, in the past year, research has shown that vaccines reduce the severity of the SARS-CoV-2 infection as well as reduces the chances of hospitalisation and death. As none of the available vaccines have an efficacy of 100 per cent, their work is mainly to decrease the risks that have been linked to the virus.
Why Do People Who Receive The Vaccine Still Get Infected?
BOOM contacted Dr. Sankaran Krishnaswamy, co-founder of Indian Scientists Response to COVID-19, and a retired professor of bioinformatics to understand the mechanisms of breakthrough infections.
"The role of the vaccines is to ensure that the frequency of deathas well as the severity of the death decreases. It does not mean that the virus has gone away. To understand breakthrough infections, it is necessary to understand the number of T-cells and B-cells that are present along with the antibodies in the immune system. If the antibody, B cells, T cell number is low, they are still susceptible to the virus," Krishnaswamy explained.
The bioinformatics professor goes on to add that the variants are also to be considered for immunity escape. Immunity escape is when the virus evolves into a different variant that is not recognised by the vaccine-induced antibodies and are thus, the antibodies do not target the variants.
Maharashtra reported two deaths among two fully vaccinated individuals who were infected by the Delta Plus variant and were above the age of 65. Both the sexagenarians had previous underlying co-morbidities and were already immunocompromised. According to an ICMR study, 86 per cent of breakthrough infections from the 677 samples they collected were due to the Delta variant.
The recent outbreaks of COVID-19 in Israel and UK have also been attributed to the Delta variant and thus there have been reports of breakthrough infection but not many deaths.
"The continuous evolution of the variants have to be also considered when we are talking about breakthrough infections. The vaccines are known to be effective against the variants but their efficacy is known to be lower than their efficacy against the original SARS-CoV-2 virus. If somebody is immunocompromised, getting exposure to the variants can be harmful for them," Krishnaswamy added.
Dr. Krishnaswamy said that booster shots for the immunocompromised should also be considered a possibility. The American Food and Drug Administration, on August 13, approved booster shots of the mRNA vaccines of Pfizer and Moderna for people living with co-morbidities.
He also stated that just like COVID-19, there were several other diseases with virus variants which were never studied because the vaccines most of the times were enough. "Small pox, measles, polio vaccines had immune escapes and breakthrough infections too, but they were never actually as keenly followed as COVID-19 is."
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