Meanwhile, experts have warned that India
needs to "significantly ramp up" the number of tests done across the country to trace Covid-19 infection if the virus is to be contained in time.
While Zydus Cadila is working on two vaccines, Serum Institute, Biological E, Bharat Biotech, Indian Immunologicals, and Mynvax are developing one vaccine each, Gagandeep Kang, executive director of the Translational Health Science and Technology Institute, Faridabad, told PTI.
Kang is also vice-chairperson of the Coalition for Epidemic Preparedness Innovations (CEPI), which noted in a recent study that the global vaccine R&D effort in response to the Covid-19 pandemic is unprecedented in terms of scale and speed.
Generally, vaccines take several months to pass the different stages of testing, and then approvals also take time. For Covid-19, we don't expect a vaccine to come in this year, agreed Rakesh Mishra, director of the CSIR-Centre for Cellular and Molecular Biology (CCMB) in Hyderabad.
Vaccine testing typically begins with animal and lab testing before going on to different stages of human testing. The human testing phase is composed of many phases, Sreekumar told PTI.
Phase one trials are small-scale, usually involving few participants, to assess whether the vaccine is safe for humans. Phase two trials often involve several hundred subjects, and mainly evaluate the efficacy of the vaccine against the disease, he said.
The final phase involves thousands of people to further assess the efficacy of the vaccine over a defined period of time, and can last several months, Sreekumar said. That is why we don't see a vaccine coming in at least a year from now.
Even after the vaccine is ready, he explained, there are a lot of challenges, including whether the vaccine is effective in all populations, and if it can be used for different strains of the novel coronavirus, which might start mutating as time passes.
There are lots of vaccines which are being tested for Covid-19, some of which are in the stage 1 clinical trial, Mishra added. But we still don't know how fast they will proceed towards a vaccine and they can take several months to reach any point, he said.
According to the World Health Organization
(WHO), three vaccine candidates are in the clinical testing phase, meaning they are able to be tested on humans, while nearly 70 are in the preclinical phase -- either in lab testing or animal studies.
Though Kang named six companies, the WHO has listed only Zydus Cadila and Serum Institute from India
as among the global firms working on a Covid-19 vaccine.
The most advanced candidates have recently moved into clinical development, including mRNA-1273 from US-based biotechnology company Moderna, Ad5-nCoV from Chinese biopharma company CanSino Biologicals, and INO-4800 from American pharmaceuticals company Inovio.
Others in this list include LV-SMENP-DC and pathogen-specific aAPC from Shenzhen Geno-Immune Medical Institute in China.
Experts believe the genome sequencing of the new coronavirus
provided by scientists in China shows it shares 79 per cent of the same genetic material as severe acute respiratory syndrome (SARS) and 50 per cent of the same material as Middle East respiratory syndrome (MERS), a species of coronavirus
which infects humans, bats, and camels.
This allows developers to use groundwork already created in research for vaccines for those viruses.
India needs to step up testing, experts warn
India needs to "significantly ramp up" the number of tests done across the country to trace Covid-19 infection if the virus is to be contained in time, experts said.
The death toll due to coronavirus rose to 414 and the number of cases to 12,380 in the country on Thursday, according to the Union Health Ministry.
While the number of active Covid-19 cases is 10,477, as many as 1,488 people have been cured and discharged and one had migrated, it said.
Data obtained from the Indian Council of Medical Research (ICMR) said, till April 14, the number of samples tested stood at 2,44,893, an increase of 27,339 from the corresponding figure till the previous day (2,17,554).
The figures for India is 2,44,893 tests averaging 177 per million of population. Spain and Italy, two countries which have also seen several thousands of fatalities, have done 6,00,000 and 10,73,689 tests respectively.
Dr Ravi Shekhar Jha, Senior Consultant and Head of the Department of Pulmonology at Fortis Escorts, Faridabad, said India is going in the right direction but it is not enough.
"Given the massive size of our population, the number of tests needs to be ramped up and should be conducted more rigorously. We need to do effective contact tracing and test them so that those people in turn do not infect others," he told PTI.