By Bhanvi Satija

Dec 24 (Reuters) - Sanofi (SNY) will buy U.S. vaccines company Dynavax Technologies (DVAX) for around $2.2 billion (1.9 billion euros), the French drugmaker said on Wednesday, a deal that will give it access to an approved hepatitis ​B vaccine.

Sanofi has made a string of acquisitions this year, as it looks to diversify growth beyond ‌its blockbuster asthma drug Dupixent. It bought UK private biotech firm Vicebio for $1.5 billion in July shortly after finalising an up to $9.5 billion deal for U.S.-based ‌rare disease drugmaker BluePrint Medicines.

The company will pay $15.50 in cash per share of Dynavax, representing a 39% premium over the vaccine maker's closing share price of $11.13 on Tuesday. Shares of Dynavax jumped 37.5% to $15.31 in U.S. in trading on Wednesday.

Sanofi said it expected to complete the acquisition in the first quarter of 2026 and said it would use available cash. The deal would not affect ⁠its 2025 financial outlook, it added.

Its shares slipped ‌0.5% .

DECLINING VACCINATION RATES

The deal marks Sanofi's second acquisition this year to expand its vaccine portfolio and comes at a time of major policy overhauls in the U.S.

Health secretary Robert F. Kennedy Jr ‍has taken aim at vaccines, cutting funding for research and ousting the head of the Centers for Disease Control and Prevention, which makes vaccine recommendations. Advisers recently scrapped a long-standing recommendation that all American newborns receive the hepatitis B shot.

Earlier this year, Sanofi had flagged lower ​vaccination rates partly due to a "negative buzz" around vaccines.

British rival GSK had also flagged pressure in U.S. vaccine sales, ‌and Australian biotech CSL delayed plans to spin off its vaccine division citing "heightened volatility" and a greater than expected decline in U.S. rates.

A GOOD FIT

The deal will give Sanofi access to an experimental shingles vaccine, which is in early stage testing. J.P. Morgan analysts said it would be a good fit for the drugmaker.

"Z-1018 does offer potential for upside to this picture if the early data can be replicated in larger trials," they said in a note, adding that Dynavax's experimental shot had ⁠potential to take a share in the shingles market, where GSK's ​Shringix is on track for sales of 4 billion euros this year.

Separately, Sanofi ​said the U.S. Food and Drug Administration had declined to approve its experimental drug tolebrutinib to treat patients with a form of multiple sclerosis.

"We believe that the FDA should also take the advice ‍of scientific experts, clinicians, and ⁠patients in this matter to ensure all perspectives are considered," said Houman Ashrafian, Sanofi's head of research and development.