CHICAGO • A Zika vaccine that Sanofi dropped in September under political pressure over pricing produced strong responses in more than 90 per cent of those taking part in an early-stage clinical trial, US researchers reported.
The results, published in the journal Lancet, offer a first glimpse at the vaccine's performance in people, and suggest it might have had a promising future.
The interim findings do not guarantee the vaccine would work, but the "immune response data in humans are very promising", said Dr Dan Barouch, a vaccine researcher at Harvard-affiliated Beth Israel Deaconess Medical Centre in Boston, where one of three trials of the vaccine are taking place.
In February last year, the World Health Organisation (WHO) declared the Zika outbreak in Brazil and elsewhere an international public health emergency because of the link between the virus and severe birth defects, touching off a scramble for a vaccine.
WHO has since downgraded the threat, but the mosquito-borne virus remains a public health concern, especially for pregnant women.
The ZPIV vaccine, made from inactivated Zika virus particles, was developed by US Army researchers, who in July last year had agreed to give Sanofi an exclusive licence to complete testing and bring the product to market.
The deal hit a snag in March this year when Vermont Senator Bernie Sanders and other lawmakers wrote letters urging army officials to cut a more favourable deal for the vaccine developed with taxpayer money.
In July, Mr Sanders proposed a rule to end "price gouging on taxpayer-funded products" by requiring federal agencies to secure agreements that such products will be reasonably priced.
Dr Amesh Adalja, a senior associate at the Johns Hopkins Centre for Health Security, said accusations like those by Mr Sanders could have a chilling effect on companies' decisions to partner with US government scientists during epidemics.
"Emerging infectious diseases such as Zika are not the same thing as making a pill for cholesterol. It's a very limited market," he said.