Covid-19: No deaths among vaccinated-reinfected people, says AIIMS study
Virendra Pandit
New Delhi: No deaths have been reported during the pandemic’s second wave in April-May 2021 among the people who had become re-infected even after vaccination against Covid-19 as they have shown enhanced immunity, according to a study conducted by the All India Institute of Medical Sciences (AIIMS), New Delhi.
It came to light in the first genomic sequence study of breakthrough infections in the country during the second wave, media reports said on Friday.
A ‘breakthrough infection’ is when someone contracts Covid-19 even after being fully vaccinated. “There will be a small percentage of fully vaccinated people who still get sick, are hospitalized, or die from Covid-19,” the US health agency, Centers for Disease Control and Prevention (CDC), had said.
The AIIMS’ first study on breakthrough infections during the April-May period indicated that despite a very high viral caseload, none of the vaccinated people died due to the disease.
It found that out of the 63 breakthrough infections, 36 patients had received two doses, and 27 had received at least one dose of the Covid-19 vaccine. Ten patients received Covishield, and 53 received Covaxin.
The B.1.617 variant, first detected in India, was divided into three lineages – B.1.617.1, B.1.617.2, and B.1.617.3. Of them, the B.1.617.2 variant, which the WHO has named Delta, was found the predominant in 23 samples (63.9 percent). Of them, 12 were among the people in the fully-vaccinated group and 11 in the partially-vaccinated group.
“While antibody levels for a subset of patients were available, they became infected nevertheless and presented to the emergency just like other patients, putting in doubt the protection offered and or clinical relevance of total Immunoglobulin-G (IgG) as a surrogate of Covid-19 immunity.”
Describing its report as ‘unique in many aspects,’ the AIIMS said that none of the investigated breakthrough infections was fatal. However, all the cases were presented with five to seven days of high-grade unremitting fever.
None of the patients had any comorbidities that could act as a predisposing factor for breakthrough infections.
In addition, differences in the prevalence of lineages based on the type of vaccine were also checked. No significant difference was observed.
Of these breakthrough infections, 10 patients — eight with double doses of vaccine and two with single-dose — had total IgG antibodies assessed by Chemiluminescent Immunoassay.
Meanwhile, two recent studies have suggested that the people infected with Covid-19 or vaccinated against it may have developed lifelong immunity against this pandemic. That did not, however, guarantee protection from re-infection but offered hope that the human body can develop antibodies that can fight Covid-19 for long.
These studies are significant as cases of re-infection left the people, including scientists, wondering whether immunity against the virus is short-lived, and they would need booster shots, annually or six-monthly, to ensure consistent immunity against Covid-19.
In these studies, scientists found that immunity against Covid-19 lasted at least for a year. But they also estimated that immunity among some people could last for decades.
