Niamh Griffin: The medical and ethical questions of Covid-19 booster vaccinations

While booster shots have been shown to be highly effective in preventing hospitalisation and death, critics say the programme will further delay rollout of the vaccine to lower-income countries

In Ireland, boosters are now available for over-60s and healthcare workers. Additionally, more than 52,000 doses have gone to younger immunocompromised people, including transplant and cancer patients. Picture: AP/Matt Rourke

Calls are growing to increase the use of booster vaccines against Covid-19 in Ireland, with medical and ethical considerations to weigh up.

The vaccine climate is very different to January, as thanks to a significant deal between the EU and Pfizer, Irish health authorities could now realistically decide on a wider booster campaign.

Indeed, in recent weeks data has emerged suggesting an extra dose is beneficial.

An American study, published on Thursday in the journal Science, found waning immunity between February and October among 780,225 military veterans who received Pfizer, Moderna or Johnson & Johnson vaccines. Led by the Public Health Institute, California it stated: “Findings support continued efforts to increase vaccination, booster campaigns, and multiple, additional layers of protection against infection.” 

In October, The Lancet published an Israeli booster study showing a third dose of Pfizer’s vaccine was estimated to be 93% effective in preventing hospital admission, 92% effective in preventing severe disease and 81% effective in preventing Covid-19 related deaths.

The European Medicines Agency (EMA) continues to evaluate the data. It has said boosters “can be considered” for healthy adults, but decisions on how to act in Ireland are made by bodies like the National Immunisation Advisory Committee (Niac).

Niac chair Professor Karina Butler said this included analysing when is the best time to give different groups a booster as well as whether it is required.

“It may be beneficial to wait longer, and in that to help with the equity in terms of distribution of vaccines on a global basis because we need to think of that as well,” she told RTÉ. 

In Ireland, boosters are now available for over-60s and healthcare workers. Additionally, more than 52,000 doses have gone to younger immunocompromised people, including transplant and cancer patients.

Calls for this to be broadened are being driven by an increase in breakthrough infections and the disproportionately high number of unvaccinated people in hospitals.

'Unvaccinated people have no protection'

“Unvaccinated people have no protection from the virus,” HSE Chief Clinical Officer Dr Colm Henry said. “Vaccination remains protective in reducing serious illness but waning immunity necessitates a booster campaign for specific groups to ensure at-risk groups are protected.” 

The HSE has about 2m vaccine doses in storage. Arrangements are in place to quickly open up delivery channels again if required, Damien McCallion, HSE lead on vaccines said.

Delivery was halted as the rollout eased, with the World Health Organization (WHO) asking countries to avoid hoarding vaccines. This is because when vaccines leave the manufacturers’ delivery streams they become ineligible for safety reasons to be returned or donated.

This potential global impact of boosters is worrying vaccine equity campaigners. Picture: Sumy Sadurni/AFP via Getty Images

This potential global impact of boosters is worrying vaccine equity campaigners. Infectious diseases specialist register and member of Doctors For Vaccine Equity Christine Kelly said delivery of vaccines to lower-income countries so far was “disappointing”. 

“The current model is that rich countries and pharma buy up the vaccines and then donate what is left over,” she said. “Even that model is not working because we are now bringing in boosters, so there won’t really be any leftovers because we are going to continue boosting.” 

She would like Ireland to align with the WHO's C-Tap programme, which promotes sharing technology so developing countries can ramp up indigenous pharma. 

On the other side, Pfizer chief executive Albert Bourla has said infrastructure is “not the bottleneck” in efforts to vaccinate the world.

“The restriction is the scarcity of highly specialised raw materials needed to produce our vaccine. These 280 different materials or components are produced by many suppliers in 19 different countries,” he said. 

Echoing this stance, a spokesman for AstraZeneca said: “We believe that an open license has the potential to actually damage the vaccine as we would lose control of safety and quality standards for our vaccine manufacturing, which are of paramount importance.” 

These issues are all feeding into booster decisions. In the meantime, the message is mask-up, limit social contacts and for eligible people to take their shots.