A Covid-19 shot in the dark

* A recent study, published in the journal Bioscience Reports, states that the virus in India shows a mutation — a sudden genetic change — in a specific area on its spike protein, giving rise to the risk that a vaccine might not produce the same response in all people

* However, the biggest challenge with any upcoming Covid-19 vaccine would be its access. The vaccine will be in short supply for many years; and manufacturing and transportation will pose severe problems

If there is one word that has been evoking considerable interest in recent times, it is the term vaccine. Last week, when the reputed medical journal Lancet published the result of the first human trial of a candidate vaccine against SARS-CoV-2, or the novel coronavirus, the outcome was cautiously welcomed in some circles. Medically called phase 1 trial, the research — which was carried out in China — looked at 108 healthy adults, and showed that the vaccine was safe and yielded protection by giving rise to a significant immune response against the virus.

Yet, while the trial seemed encouraging, many scientists — including the author of the study — were sceptical of the results. “These results should be interpreted cautiously,” said Wei Chen, study-author and a professor attached to the Beijing Institute of Biotechnology, in a statement.

According to Chen, the ability to trigger immune responses against SARS-CoV-2 does not necessarily suggest that the vaccine will provide protection against Covid-19. “This result [of the phase 1 trial] shows a promising vision for the development of Covid-19 vaccines, but we are still a long way from this vaccine being available to all,” he adds.

Caution was also voiced by Australia’s prestigious Monash University, Melbourne. “Vaccines are complex to make, with most taking 10 to 15 years and three phases of testing to enter the market,” it said in an article last week in the University’s web publication Lens .

In different parts of the world, eight vaccines are currently undergoing phase 1 trials. But at the earliest, a Covid-19 vaccine may only be available in 2021, says the Journal of the American Medical Association .

In the UK, human trials are being conducted by Oxford researchers for a suitable vaccine, and volunteers are being recruited for further [phase 2 and 3] trials. Meanwhile, American pharmaceutical company Moderna announced the results of its Covid-19 candidate vaccine’s phase 1 trial last week. It claimed that the vaccine could induce antibody response against the virus.

Not everybody is convinced of its efficacy, though. “Some vaccine experts have already expressed scepticism at the Moderna results, which they say have not been published in scientific journals, and were released only in part,” the Monash University article states.

Everybody is waiting for a Covid-19 vaccine, but will it truly work in a large country such as India, where diversity in the population (physical, genetic, financial and so on) is a crucial factor?

“There may be a small risk that a vaccine [for Covid-19 in India] might not produce the same response in all people,” warns Arthur Caplan, eminent medical ethicist, professor and head of the division of medical ethics, New York University Langone Medical Center, US. “Underlying diseases, prior infections might limit [the vaccine’s] efficacy or create more risk,” he tells BL ink .

A vaccine should have the potential to provide protection even in the case of anticipated future mutations of the virus, stresses Asis Manna, professor and vice-principal, Infectious Diseases and Beliaghata General Hospital, Kolkata. While safety should be the primary concern of researchers, they must also focus on economy, ease of vaccine administration, temperature tolerance and optimum efficacy, he adds.

It is imperative to determine how a particular vaccine against SARS-CoV-2 is likely to work on different people in India and in different geographic and climatic conditions, says Shantanu Panja, consultant ENT specialist at Apollo Gleneagles Hospital, Kolkata.

“It is premature to gauge the efficacy of any vaccine for Covid-19 on the Indian population unless it is tried and tested with utmost safety in this country,” he maintains. “To tackle Covid-19, we are expecting to develop a vaccine with the touch of a magic wand. Under normal circumstances, a vaccine takes 3-5 years to develop,” Panja says, stressing the need for rigorous trials.

There are other aspects that researchers have to deal with. A vaccine is often targeted against the structural proteins of a virus, explains Upasana Ray, senior scientist at the infectious diseases and immunology division, CSIR-Indian Institute of Chemical Biology. “A virus, however, also has important non-structural [not related to its structure] proteins crucial for its lifecycle... We should also consider these non-structural proteins for vaccine designing... and this might provide long-lasting protection,” she adds.

Caplan, however, believes that the biggest challenge with any upcoming Covid-19 vaccine would be its access. According to him, the vaccine will be in short supply for many years; and manufacturing and transportation will pose severe problems. “So, which nations and which citizens get them first, I fear, are [decisions] likely to be fuelled by money, self-interest, [and] black markets and not epidemiology,” he cautions.

Sanjeet Bagcchi is a physician and an independent writer based in Kolkata

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