The pharmaceutical industry has warned against straying from tried-and-tested dosing intervals for Covid-19 vaccines, saying doing so risks public confidence in the shots.
The main pharmaceutical lobby groups in the US and Europe on Wednesday said they supported “adhering to the dosing that has been assessed in clinical trials” and that “emerging discussions regarding dosing strategies” may not be supported by drug labels or published data.
Any changes in dosing and inoculation schedules “should follow the science and be based on a transparent deliberation of the available data”, the International and European Federations of Pharmaceutical Manufacturers & Associations and US industry groups BIO and PhRMA said in a joint statement.
The UK has opted to extend the dosing regimen for the two approved vaccines it is currently deploying against coronavirus — those made by BioNTech/Pfizer and Oxford/AstraZeneca — to 12 weeks, igniting a fierce scientific debate and attracting criticism from manufacturers.
Other countries, including Germany and Denmark, have either opted for the same approach or expressed interest in pursuing it, though at a maximum of six weeks between the first and follow-up shot.
But US agencies have argued against spacing the doses out, with health secretary Alex Azar on Tuesday calling it “reckless” and the Food and Drug Administration warning it is “counter-productive”.
Observers have said the UK’s “pragmatic” decision highlights the public health need the country is facing amid constrained vaccine supply. The 12-week gap is considerably longer than the 21 days focused on in clinical trials for the Pfizer jab.
Spacing out doses has wide theoretical backing as it tends to spur stronger immune responses. It is also underpinned by large-scale empirical evidence for other vaccines, though is not for coronavirus.
The World Health Organisation and the European Medicines Agency allow a maximum interval of six weeks, though they recommend following the vaccine schedules adopted in trials. Their guidelines are not valid for the Oxford/AstraZeneca vaccine, which is only approved in the UK. AstraZeneca is a member of some of these lobby groups.
Experts have said a lack of clear communication around the strategy could cause hesitancy among potential recipients, making large-scale vaccination campaigns useless. The approach could also spur the emergence of vaccine-resistant strains, though UK health authorities have said this risk is small given the potential benefit of achieving wider, if not clinical trial-grade, immunity in a larger part of the population.
The UK has also made emergency plans to mix different coronavirus vaccines, though health authorities say the approach is not recommended and would only be used in extremely limited circumstances.
“It is vital to preserve, build and sustain public confidence in Covid-19 vaccination by continuing to make and communicate policy decisions based on robust scientific evidence,” the lobby groups said in their statement. They encouraged more studies to produce better information on the changes.
“Only then can we bring this pandemic to an end.”
Additional reporting by Hannah Kuchler in New York