Rajendra Kapila, US- based world renowned infectious diseases expert, has died of Covid-19 in India. He was aged 81.  Kapila, who had traveled to India to take care of his family, was supposed to return to the US in the second week of April but had to be hospitalized in Delhi after testing positive for the virus

However, the intriguing thing about the death of the University of Rutgers Professor who had practised medicine in the United States for 50 years and known for his extensive work on HIV/AIDS is that he and his wife Dr Deepti Saxena Kapila, had taken both doses of the Pfizer vaccine prior to his arrival in India.

Kapila’s colleagues confirmed his death on Twitter Wednesday, expressing their grief and applauding Kapila’s work.

“We have lost a giant in infection disease,” wrote Nancy Connell, Professor and Vice-Chair for research in the Division of Infectious Disease in the Department of Medicine at Rutgers New Jersey Medical School, adding that Kapila “served as a leader in global infectious diseases” at Rutgers and the department “will be forever grateful for his contribution to global ID and remember his extraordinary diagnostic talent.”

Given Kapila’s age, he was within an age group that is vulnerable to complications from the virus. He also had diabetes and heart complications, his ex-wife Dr. Bina Kapila told ABC7.

“For the last one year I have been working at a Covid-19 lab in New Jersey and had ensured a safe environment at home. It is ironic that we came to India for two weeks and he contracted it here,” Dr Deepti, who specialises in microbiology, was quoted as saying by the Hindustan Times.

Still, Bina, to whom Kapila was married for 40 years before they divorced a decade ago, has expressed shock over his death, saying he had decided he would stay in New Delhi for one week to help his family and provide his expertise.

“What can go wrong in one week? So he was only going to go for one week,” she said. She also said her ex-husband was a uniquely gifted medical professional. “He was so brilliant when we were in college, in medical school, that the professors of medicine after they gave a lecture, they would come to him and ask him, ‘did I cover everything?'” she told ABC7.

Kapila’s death has not only sent shock waves across the world but has also raised concerns over the efficacy of the Pfizer vaccines against the new double mutant variant first found in India. Although there is no direct evidence showing reduced efficacy of Pfizer vaccines, previous studies show their efficacy against other variants is not guaranteed.

However, according to what Tao Lina, a Shanghai-based vaccine expert, told the Global Times on Wednesday there is no direct evidence showing whether the Pfizer vaccine is effective on this variant or not, while noting that China-developed inactivated vaccines might be more effective against the double mutant than mRNA ones.

“Technically, Pfizer vaccine uses human cells to synthesize S protein in the human body to produce antibodies, whereas China-developed vaccines, including Sinovac and Sinopharm, use inactivated viruses as antibodies, which may cover more variants than Pfizer does,” Tao said.

Tao added that while the efficacy of Pfizer against the new double mutant remains unknown, previous medical studies suggested a reduced efficacy rate of Pfizer shots against other Covid-19 variants.

“The human body develops resistance to vaccines, and the variants may need even five or six doses of vaccine instead of merely two to produce enough protection,” he noted.

Still, according to a press release on its official website, Pfizer said its vaccines show a 95.3 percent efficacy rate against severe COVID-19 cases, which has been defined by the US Food and Drug Administration.