European Court says scientific proof of causation is not required under the EU Product Liability Directive


On 21 June 2017 the Court of Justice of the European Union (the CJEU) delivered its judgment in Case C-621/15, a request for preliminary ruling under Article 267 TFEU from the Cour de Cassation in France on the burden of proof faced by Claimants who allegedly have suffered harm from a defective vaccine. The Court held that Directive 85/374 (the “Product Liability Directive”) does not preclude national evidentiary rules which presume a causal link between the defect of a vaccine and a disease when supported by serious, specific and consistent evidence, in the absence of scientific evidence about a causal relationship.
In 1998 & 1999 J.W. was vaccinated against Hepatitis B. Shortly after he developed multiple sclerosis. After his death in 2011, his family brought a claim for damages against the manufacturer of the vaccine, Sanofi Pasteur and three other defendants, based on the French Civil Code. According to the relevant provision of the French Civil Code, a causal link may be presumed if a disease manifests itself shortly after administration of the allegedly defective drug and there are no personal or family antecedents related to the disease, even if medical research does not in general, confirm the existence of such a link. The action was upheld at first instance and overturned on appeal, the family eventually brought the case before the Cour de Cassation in France who then made a referral to the CJEU.
CJEU Referral
The Cour de Cassation referred three questions to the CJEU for determination. In simple terms, they wanted to clarify whether a national procedural rule allowing serious, specific and consistent presumptions to prove the existence of a defect and its causal link with a medical condition, notwithstanding the lack of scientific evidence, was compatible with the Product Liability Directive
The Product Liability Directive
The Product Liability Directive addresses the approximation of the laws, regulations and administrative provisions of the Member States concerning liability for defective products. Under Article 4 of the Product Liability Directive a person injured by a defective product must prove the damage, the defect and the causal relationship between defect and damage. Therefore, the burden of proof rests firmly with the injured person, the Claimant. The Product Liability Directive is clear to the extent that if the injured party fails to discharge the burden of proof, the claim will fail. The standard of proof and what evidence is required to meet that standard are not, however, harmonised by the Product Liability Directive.
The CJEU concluded that the concept of a causal relationship was not strictly defined in the Product Liability Directive, unlike the concept of “defect”. Therefore, they were of the opinion that it was for the relevant Member State court to determine how evidence was to be obtained, what evidence would be admissible and the principles around the probative value of evidence that was relied upon.
In those circumstances, the CJEU was satisfied that an evidentiary rule based on serious, specific and consistent evidence in the absence of scientific consensus (as seen in the French Civil Code), does not violate the Product Liability Directive, as it remains for the injured person to prove the various elements of his or her case. The court held that excluding a method of proof other than that based on medical research would be inconsistent with the objectives of the Product Liability Directive and the principle of effectiveness as this could result in it becoming excessively difficult to establish producer liability.
While the court confirmed that for a relationship between defect and damage, it is not a requirement that the causal relationship be established by any kind of specific evidence, medical or otherwise, they did caution that national courts must be satisfied that the evidence is sufficiently serious, specific and consistent to determine that the existence of a defect in the product is the most plausible explanation as to the cause of the disease.
The Court’s decision heralds positive news for Claimants in France (and other Member States who may have a similar procedural rule). In cases where there is scientific uncertainty and no clear evidence to either side of the causation equation, the Claimant does not automatically lose their case for inability to prove a scientific link and can attempt to use other factors (like proximity of time and lack of family history) to convince the court to find a link. However, the burden of proof to establish a causal link and the related hurdles still firmly rests with them. In addition the CJEU did strongly emphasise that manufacturers should be given an opportunity to present counter evidence, including countering scientific evidence.
Notwithstanding those remarks, the decision has understandably been met with sharp criticism from the science and medical industries. Despite some of the media reporting of the decision, it is important to stress that the decision does not permit courts to ignore science or medical research. However, it is fair to say that this decision has in effect lowered the evidence standard in vaccine liability cases by permitting reliance on correlations that do not equal causation. This could result in scientifically unsupported decisions in favour of Claimants claiming injury where there is no compelling evidence that vaccines caused the disease or injury the Claimant is suing over.
It remains to be seen what impact this decision will have on the Cour de Cassation’s decision in J.W’s case, however, the CJEU’s conclusion does not contradict the most recent decision from Paris which was that J.W failed to prove causation. We wait to see whether that decision will stand.

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