Sanofi to buy Dynavax for $2.2B: big bet on adult vaccines (hep B + shingles)

What happened

Sanofi ($SNY) agreed to acquire Dynavax ($DVAX) in an all-cash deal valued at about $2.2B (reported price: $15.50/share). The goal is to strengthen Sanofi’s adult vaccine lineup with Dynavax’s marketed hepatitis B vaccine (Heplisav-B) and an early-stage shingles candidate (Z-1018). Deal is expected to close in early 2026, subject to approvals.

Why markets care

Adult vaccines are a growth battleground: Big Pharma is willing to pay for differentiated schedules, better adherence, and large adult catch-up populations.

Consolidation signal: A credible buyer paying a meaningful premium can re-rate other vaccine-focused biotechs and push more deal chatter.

Competitive pressure: Incumbents in shingles and hepatit ...