If a Brexit deal is not realized, shipments of flu vaccines could be affected.

As the lack of an agreement between the UK and EU regarding Britain’s exit from the European Union looks more likely, many pharmaceutical companies are stockpiling products in order to be able to meet demand in all countries. There is concern that if no Brexit deal is made, drug shipments will be held up at borders. 

Stockpiling seasonal flu vaccines is not possible, however, as they cannot be made in advance. As the largest flu vaccine supplier, Sanofi is looking at the measures it may need to take to ensure seasonal flu shots can reach customers on time, according to the company’s head Hugo Fry. 

The flu vaccine cannot be produced until the upcoming season’s circulating flu strains have been determined. The viruses must then be cultured, the vaccines formulated and then subjected to various tests in order to obtain regulatory approval. Millions of doses must then be produced and delivered to various markets in August for early vaccinations. Flu season begins in earnest in October, and any delay of the vaccine leaves less time for people to get protected. 

For the 2017-2018 flu season, Sanofi sold over 5.7 million doses of its quadrivalent flu vaccine in the U.K., according to Sanofi spokesperson Louise Brant. In the past, Sanofi’s vaccines have been delivered to the UK via the English Channel. The company is considering for this year flying doses to a predetermined spot in the U.K. where the government would release the delivery instantly. A second option would be to use trucks marked in such a way as to allow rapid passage through customs.