A study conducted by the All-India Institute Of Medical Sciences (AIIMS) in Delhi has found that during the months of April and May 2021, no vaccinated patient died after getting re-infected with Covid-19.
This is reported as India’s first genomic sequence study of breakthrough infections during the second wave of Covid-19 in India. A breakthrough infection occurs if one contracts Covid-19 after being fully vaccinated. According to the US health agency, Centers for Disease Control and Prevention (CDC), a small percentage of completely vaccinate people will still get sick, hospitalized, or even die from Covid.
The study undertaken on breakthrough infections during the April-May period by AIIMS Delhi found out that despite a very high load, none of the vaccinated persons died from the viral disease. Out of the 63 breakthrough infections, 36 received two doses of the Covid-19 vaccination, while 27 received at least one dose. While ten patients received Covishield, Covaxin was given to 53.
As per the study, SARS-CoV-2 lineages could be assigned to a total of 36 (57.1 %) samples – 19 (52.8 %) in patients who completed both doses and 17 (47.2 %) in patients who completed only a single dose.
The B.1.617 variant, first detected in India, was split into three lineages – B.1.617.1, B.1.617.2, and B.1.617.3.
The B.1.617.2 variant was found to be the predominant lineage in 23 samples (63.9 %). They were divided into two groups, 12 were among the people in the fully vaccinated group, and 11 were in the partially vaccinated group.
Lineages B.1.617.1 and B.1.1.7 were found in four (11.1 %) and one (2.8 %) sample, respectively.
The AIIMS report suggested that although antibody levels for a subset of patients were available, they became infected even so and were presented to the emergency ward just like other Covid patients, putting in doubt the protection offered and or clinical relevance of total IgG as a surrogate of Covid-19 immunity. AIIMS also claimed that the present report is unique in many aspects.
While all the cases were presented with five to seven days of high-grade continuous fever, none of the investigated breakthrough infections were fatal.
The patients were between the age group of 21-92 years with a mean age of 37. Among them, 41 were male and 22 were female. None of the patients had any comorbidities that could have acted as a risk factor for breakthrough infections.
As lineage B.1.617.2 was also prevalent in this group, any significant variation in lineages between completely and partially vaccinated samples and on the type of vaccine were investigated. No significant difference was found in both groups.
Of these breakthrough infections, 10 patients (8 – fully vaccinated and 2 – partially vaccinated) developed total Immunoglobulin G (IgG) antibodies, evaluated by Chemiluminescent Immunoassay.
Out of these 10 patients, six patients had IgG antibodies a month before the covid-19 infection, while four other developed antibodies after the disease.
Recently, two studies suggested that people infected with SARS-CoV-2 or fully vaccinated against it may have lifelong immunity against the viral infection. Although there is no guarantee of protection from re-infection, the studies offer hope that the human body can develop antibodies that can fight Covid-19 for long.
Scientists in these studies found that immunity against Covid-19 lasted for a minimum of 1 year, but in some people, it could last for decades.