Drugs company Sanofi could airlift supplies of its flu vaccine into the UK to avoid disruption following Brexit.
Ferry ports are expected to experience widespread disruption if the UK leaves the EU without a deal, and Sanofi warned that it is not possible to stockpile its flu vaccine, unlike other medicines.
Speaking to the BBC, Hugo Fry, Sanofi's UK managing director, said: "We prepare in different ways and have prepared many different routes into the UK.
"If we have to in the end, we will airlift it in."
He added: "We are eating the cost of that but patients and citizens are our primary concern, so we're quite happy to take that cost and make that planning."
In August last year, Sanofi said it was increasing its stockpiles to ensure it had 14 weeks worth of medicines.
Mr Fry added: "We're doing everything possible to make sure that everyone will get their medicines and vaccines so that they can be reassured and they don't have to worry about it."