EU antitrust regulators are investigating Sanofi over allegations that it broke competition rules by running a "misleading" campaign disparaging the only rival flu vaccine recommended for vulnerable patients. The European Commission has opened a formal probe into how the French drugmaker marketed its own shot against a competing product, a move that places routine vaccine promotion under the lens of EU competition law.

What the European Commission alleges against Sanofi

According to the Commission, Sanofi portrayed the Fluad vaccine, marketed by rival CSL Seqirus, as inferior to its own Efluelda vaccine in a communication campaign aimed primarily at healthcare professionals in Germany and France. The Commission says Sanofi holds a dominant position in both of those national markets, which is central to the case.

Regulators add that the campaign also appeared to contradict national vaccine recommendations in several EU member states, suggesting the evidence for using CSL's Fluad was weaker than the evidence for Sanofi's Efluelda. Efluelda is a high-dose influenza vaccine specifically designed to give stronger protection to people over 60, the same older, higher-risk group for whom Fluad is recommended.

The probe is at an early stage, and opening an investigation does not prejudge the outcome. The Commission will now gather evidence on whether the marketing crossed the line from competitive promotion into anticompetitive disparagement.

Why the Sanofi flu vaccine probe matters

Under EU law, disparaging a competitor's product can amount to an abuse of a dominant market position, and the bar for acceptable conduct rises sharply once a company is deemed dominant. When the products in question are medicines for at-risk groups, the stakes extend beyond market share to public health.

  • Company under scrutiny: Sanofi, said to be dominant in Germany and France
  • Product promoted: Efluelda, a high-dose flu shot designed for people over 60
  • Rival named: Fluad, marketed by CSL Seqirus
  • Core concern: a campaign targeting health professionals that allegedly misled them and contradicted national guidance

The Commission's theory is that by framing Fluad as inferior, Sanofi may have steered prescribing decisions in markets where it already holds sway. That is precisely the kind of conduct competition enforcers scrutinise most closely, because a dominant firm's words can move a market in ways a smaller rival's cannot.

What it means for vaccine marketing in Europe

The case highlights how pharmaceutical marketing increasingly intersects with antitrust enforcement across Europe. Drugmakers routinely promote the clinical advantages of their products to doctors, but the line between robust marketing and unlawful disparagement is exactly what this investigation will test. A finding against Sanofi could reshape how dominant manufacturers communicate about competing vaccines, especially those aimed at protecting older adults.

The timing carries weight because both shots target people at higher risk from influenza. Messaging that influences which vaccine older patients receive has real public-health consequences, not just commercial ones. For more on regulation and corporate conduct, see our business coverage, and follow related developments in health news.

Sanofi antitrust probe: key questions

What is Sanofi accused of?

The European Commission alleges Sanofi ran a misleading campaign that portrayed CSL Seqirus' Fluad vaccine as inferior to its own Efluelda shot, aimed at healthcare professionals in Germany and France where Sanofi is said to be dominant.

Why are flu vaccines an antitrust issue?

Disparaging a competitor can be an abuse of a dominant market position under EU law. Because both vaccines target older, higher-risk patients, regulators view misleading promotion as both a competition and a public-health concern.