Covid-19 booster shot debate heats up amid breakthrough infections

Need for a booster dose has become a hotly debated topic. Here's a look at the discussion around the world

Worries around breakthrough infections and the duration for which vaccines protect us from Covid-19 brought the booster dose into the spotlight. As countries across the world from Thailand to Turkey, Germany to Uruguay, vaccinate their population with both doses of the coronavirus vaccine, talk of a booster dose has gathered steam.

France and Uruguay are among the few countries that have already begun administering booster doses to fully vaccinated adults, while some including Singapore, South Korea and plan to start on the additional dose either this month or the next.

There has been much discussion about the need for a third dose when many countries are yet to receive their second. Here's a look at the course of the booster dose debate.

Boost to the third dose in the US

Much of the booster dose discussion has been centred around the United States, where Biden in August urged for a third dose of the vaccine for all adults, starting September 20. Booster doses were approved for immunocompromised individuals earlier that month by the Food and Drug Administration (FDA) and Centers for Disease Control (CDC). In a setback to Biden's ambitious vaccination plan announced mid-August, the FDA had rejected the idea of booster doses for adults above 16 years of age. But it has now given the nod to give booster vaccines for those aged 65 and above.

The US started talking about the booster dose when the more infectious Delta variant of the virus landed on American shores, increasing Covid-19 hospitalisations in a number of states a few months ago, especially Florida.

According to the CDC, booster doses are to be given to fully vaccinated individuals (usually two doses, or one in the case of Johnson & Johnson) after eight months. Booster doses in simple terms serve to remind the immune system of the response needed to fight a pathogen after the effect of the initial doses wanes away.

A booster dose can wait till low-income countries vaccinate

The World Health Organization (WHO) has sought a moratorium on booster doses till the end of the year, urging rich nations to allow lower-income countries — that have barely vaccinated a tenth of their population and are dependent on vaccine supply from COVAX — to administer the first and second doses.

“I will not stay silent when companies and countries that control the global supply of vaccines think the world's poor should be satisfied with leftovers,” WHO chief Tedros Adhanom Ghebreyesus had told a news conference, targeting rich nations such as the US. He pointed out the inequity of vaccine access with Africa, where only four countries had managed to vaccinate 10 per cent of its population.

India made clear its stance on Thursday when Indian Council of Medical Research (ICMR) General Director Balram Bhargava asserted that a booster dose was not the central theme of India's vaccination drive at the moment in either scientific discussions or the public health domain.

"Getting the two doses remains the major priority," Bhargava said.

"Several agencies have recommended that antibody levels should not be measured...but the important understanding is that full vaccination of both the doses is absolutely essential and there should be no breakage in that," he had said.

Adar Poonawalla, who helms the world's largest vaccine manufacturer, Serum Institute of India, said on Friday during a media interaction that it was "unethical" to offer booster doses in India at the moment when certain populations have not even got two doses.

He added it was "not right" to roll out booster shots when poorer countries have "not been able to get the vaccines purely because the rich nations have taken away most of the vaccines".

A study conducted by The Lancet stated that it was "not appropriate" to administer booster doses for the general population as vaccine efficacy against severe Covid-19, including the delta variant, was more than enough.

The review by experts, including those from the WHO and the FDA summarised the currently available evidence from randomised controlled trials and observational studies published in peer-reviewed journals and pre-print servers.

Results reported from the observational studies show that vaccination had 95 per cent efficacy against severe disease both from the Delta variant and from the Alpha variant and over 80 per cent efficacy at protecting against any infection from these variants.

If vaccines are deployed where they would do the most good, they could hasten the end of the pandemic by inhibiting further evolution of variants, the authors of the study, one among whom was WHO Chief Scientist Soumya Swaminathan, noted.

(With agency inputs)

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