Why vaccine hunt could yield multiple winners

On Wednesday, the UK approved Pfizer’s vaccine, the first to get the regulatory nod in a western country, and Britons could begin getting the jab next week. Pune-based Serum Institute says it’s going to seek emergency approval for its Covishield vaccine for which it is partnering with AstraZeneca and Oxford University. It looks like the search for a vaccine is set to throw up several winners. Where one scores on speed and scalability another allows greater ease of production and distribution. Regardless of whichever is first off the blocks, several candidates look set to swell the Covid vaccine arsenal.
LEADING THE CHARGE
The ones in line for emergency nod
Among the frontrunners likely to hit the markets first are vaccines under development by the likes of pharma giants Pfizer and AstraZeneca, and those produced by Russian state researchers and Chinese institutes. The expedited timelines of these vaccines have raised questions over trials and safety standards, but efficacy data has prompted developers to go ahead with the process of rolling these out within the shortest possible deadlines. Some, like the Russian Sputnik V — also being trialled in India by Dr Reddy’s Laboratories — multiple Chinese vaccines, and now the Pfizer candidate, have received emergency use approval from health authorities. These vaccines are not all similar as researchers try everything from the traditional inactivated virus platforms to ones based on never-approved-before DNA and RNA platforms.
THE HOME TEAM
Indian vaccines in the works
Phase 3 Covaxin, the first Indian Covid vaccine candidate to enter clinical trials, is being developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR). This vaccine uses an inactive version of the virus to prompt the immune system to produce antibodies. The Phase 3 human trials are under way at AIIMS, New Delhi. Trial results are expected in early 2021 and the vaccine could be ready for distribution by next June.
Phase 1/2, combined phases
Hyderabad-based Biological E licensed the knowhow from Baylor College of Medicine — which had started work on a SARS vaccine in 2002 — and has launched human trials for its protein subunit vaccine. These vaccines often need to be combined with an adjuvant, or a booster, which in this case is being made by Dynavax, another US company. Results are expected by February 2021.
Phase 2 Ahmedabad-based Zydus Cadila is testing two versions of its vaccine, called ZyCov-D, one of which uses molecular DNA while the other uses a live measles viral strain to elicit an immune response. The vaccine is expected to be available by March 2021.
Prepping for human trials
Mynvax, a startup incubated at the Indian Institute of Science, Bangalore, is pursuing a heat-tolerant vaccine that its makers say is ready for tests and human clinical trials. According to cofounders, their vaccine can be stored at 37°C for over a month without losing its effectiveness.
Another candidate, being developed by the Pune-based Gennova Biopharmaceuticals, could reportedly be ready by March 2021. It is an m-RNA vaccine being developed in partnership with US-based HDT Biotech Corporation. This vaccine has also got funding from the Centre’s Department of Biotechnology and is looking to begin clinical trials in December.
A longer wait for India’s billion-dose Novavax order
After getting promising results from preliminary studies in monkeys and humans, US-based Novavax launched a Phase 2 trial in South Africa in August. The following month, Novavax launched a Phase 3 trial enrolling up to 15,000 volunteers in UK. It is expected to deliver results in early 2021. A larger Phase 3 trial in US is expected to launch by the end of December.
In September, Novavax reached an agreement with the Serum Institute of India that they said would enable them to produce as many as 2 billion doses a year. The Indian government has already secured a billion doses.
Nose for a vaccine
It is the upper respiratory tract — which includes the nose, tonsils and adenoids — which the SARS-CoV-2 virus initially attacks but this region has not exactly been the focus of research for combating the disease, some experts have pointed out. Focusing on mucosal immunity (involving mucous membranes of the nose and mouth) might enable the development of, say, a nasal vaccine that could be easier to store, transport and administer. Several such Covid vaccines are now under development but how far along they are is unknown.
Source: NYT, media reports