India is in a fix about Covid-19 booster doses. It’s becoming abundantly clear globally that boosters are the need of the hour as the highly mutated Omicron variant sweeps the globe.

But the problem for India quite simply is that Covishield, made under licence from Oxford University/AstraZeneca and which has been administered to around 88 per cent of adults in the country, isn’t suited to be used as a top-up dose for people who have already had two jabs of the vaccine, scientists say.

Says top virologist Shahid Jameel: “A third dose of AstraZeneca will not be very effective due to the nature of this vaccine.” AstraZeneca uses a genetically modified chimp cold virus. “Repeated boosters with that will mean boosting chimp protein responses at the cost of spike protein responses,” he said. The newer technology “mRNA vaccines make only spike proteins so they can be used as boosters in people who got them earlier,” he added. Around 88 per cent of Indians have received the Covishield vaccine.

Jameel’s comments came as The Indian Express reported the National Technical Advisory Group on Immunisation, the body which guides the government on vaccination policy, had reached a preliminary consensus that any booster dose should be of a vaccine different from the first two jabs.

UK zeros in on two

In the UK, the Joint Committee on Vaccination and Immunisation has said only the Pfizer and Moderna vaccines which both use mRNA technology, should be administered as booster shots. A UK trial found the Pfizer vaccine produced the strongest booster response out of seven possible options. The UK decision has come as a big blow to the Anglo-Swedish AstraZeneca which has been used for 53 per cent of the jabs in Britain. UK scientists also report that early analysis shows that a booster jab prevents around 70-75 per cent of people infected with Omicron from getting any symptoms.

The recommendation against using AstraZeneca for booster shots also puts India in a bind. The only vaccine produced currently in bulk in India is Covishield and the key question is whether India has enough supply of the right vaccines to do the job.

Jameel says there are various Indian vaccines that could potentially be used as boosters. These include Covaxin, manufactured by Bharat Biotech, that might be used for people who earlier received Covishield and vice versa. Then, there’s the DNA vaccine ZyCov-D, made by Zydus Cadila. Also, there’s Covovax, a protein vaccine being made by Serum Institute. Thirdly, there’s Corbevax-E a protein vaccine from pharma company Biological-E.

Cheaper protein vaccines

Jamal notes Covovax and Corbevax-E are not yet licensed. However, he says the trial data is already with the (DGCI) Drugs Controller General of India and he says the regulatory process should be “speeded up.” Half of India’s adult population has been double-jabbed while 85 per cent has received one injection. Bharat Biotech’s Covaxin is an expensive vaccine and the cheaper protein vaccines could be used instead. “That will provide volume,” he said.

There is also another possible candidate, India’s first homegrown mRNA Covid-19 vaccine, developed by Gennova Bio,part of Emcure Pharmaceuticals, which is still to be approved. This vaccine offers the convenience of not requiring ultra-cold storage unlike the mRNA vaccines developed by Pfizer and Moderna.

Neither Pfizer nor Moderna is available yet in India as the government has rejected the US companies’ demand for legal immunity over any side effects from the use of their shots.

Booster dosing study

Virologist Gagandeep Kang has called for people who’ve had two doses of Covaxin around three to six months ago to volunteer for a ‘booster dosing’ study. Amongst other things, the study will look at the impact of mixing Covaxin and Covishield. “The sooner we recruit, the sooner data will be available! Needs a month after all recruitment is complete for the first complete set of samples and a week after that, finish testing,” Dr Kang said.

Doctors and health researchers say that a mix-and-match strategy where a different vaccine is given as a booster is showing strong results in tests. In Britain, trials have shown that the Pfizer vaccine is well-tolerated as a third jab. A study by University Hospital Southampton also indicated that a half dose of the Moderna vaccine would be sufficient as a booster.

Virologist T. Jacob John warned that the government mustn't drag its heels in deciding on booster doses. “By the time you do studies and find it is an excellent defence against the Omicron, it will be too late. He added: “We have to learn to build the boat while we sail it.” Jameel says that the “immunocompromised must get boosters on priority.”

Govt in a fix

However, the Indian government is also in a fix because a huge number of people have not finished their vaccine course and some have not even received their first dose. WHO has recommended broadly that a first round of vaccinations should be completed before booster doses are given. Also, the government has to figure whether we should offer vaccinations to children below 18 as is being done in the US and several other countries.

UK Prime Minister Boris Johnson announced late Sunday the country would use the army to start rolling out one million booster jabs a day, up from 530,000 a day, to battle a “tidal wave of Omicron” and “reinforce our wall of vaccine protection.” Omicron cases are rising so fast in the UK the Health Security Agency has warned that the country could have one million cases of Omicron by the end of December. The US has authorised a single booster dose of Pfizer for all individuals 16 years of age and older in the country which has Omicron in 22 states.

Professor Eleanor Riley, professor of immunology at Edinburgh University warned in the Daily Mail that the variant was spreading so quickly in the UK that everyone would come into contact with it, “unless you’re a hermit”. One air traveller who returned to Kerala from the UK tested positive for Omicron on Sunday, bringing the total number of cases of the new variant in India to 38.

Lockdowns needed

Modelling by the London School of Hygiene and Tropical Medicine suggests that the UK may have between 25,000 and 75,000 deaths in the next five months even with the vaccination campaign in full swing. The researchers said stronger lockdown-type measures would be needed and that pubs and restaurants should be shut for now.

The UK Health Security Agency says two doses of both the Oxford/AstraZeneca provides "much lower levels" of protection against symptomatic (Omicron) infection compared to the currently dominant Delta variant of COVID-19.” However, a booster dose seems to increase immunity against the new variant, based on data from 581 Omicron cases.

"The preliminary data showed effectiveness against the new variant appears to increase considerably in the early period after a booster dose, providing around 70-75 per cent protection against symptomatic infection,” the agency said.

UK immunologist Danny Altmann told CNBC someone who’s had two doses whose vaccine immunity has waned has “little protection against (Omicron) infection. If you’ve got a booster or have two doses plus prior infection, you’re probably in the safe protective zone.”

The saving grace

The importance of a third vaccine dose is highlighted by research from the Africa Health Research Institute in South Africa which showed a 41-fold drop in the ability of antibodies from double-vaccinated people to eliminate the virus.

However, Jameel says India has one factor that may keep widespread infections at bay. “We are in serious trouble (about booster doses).” But he adds: “The saving grace for India is that a very large number of double vaccines in India were also exposed to the virus at some point without knowing it. That acts as a natural booster.”The World Health Organization confirmed late Sunday that Omicron appeared to be more transmissible than previous variants. It also said Omicron’s symptoms appeared to be milder. But doctors warn that if Omicron keeps growing exponentially, infecting millions, health systems around the world could break down, even if only some of the cases are serious.