On June 21 the CJEU decided in the case of product liability related to a potentially defective vaccine - W and Others (C-621/15). Mr W was vaccinated against hepatitis B in the years 1998-1999 with a vaccine produced by Sanofi Pasteur. He was diagnosed with MS in November 2000, which first led to his disability from work, then needing round-the-clock care, and finally his death in October 2011. Together with his three family members he raised a claim against Sanofi Pasteur in 2006, arguing that his illness resulted from the administration of the vaccination.
Vaccinations have long been a controversial topic as the available medical research has not been able to either conclusively prove their detrimental effects to human health or to conclusively disprove them. This is at least confirmed in this case with respect to the lack of medical research establishing a relationship or lack thereof between the hepatitis B vaccination and the multiple sclerosis disease (par. 30). Article 4 of the Product Liability Directive requires the consumer to be able to prove not only the damage, and its cause but also the causal link between the two. What evidence was submitted in this case? Mr W and Others claimed that the short period between the vaccination and the appearance of first symptoms of MS should be considered, as well as the fact that there was no trace of family history of this disease. These facts "are such as to give rise to serious, specific and consistent presumptions as to the existence of a defect in the vaccine and as to there being a causal link between the injection of the vaccine and the occurrence of the multiple sclerosis." (par. 11)
In French law, which was applicable to this case, the Cour de cassation stated previously that with regard to the defective vaccines and the liability of pharmaceutical companies for their production, the causal link could be derived from "serious, specific and consistent presumptions". So even if the medical research does not confirm a relationship between the vaccination and the occurrence of the disease, the court could establish the defect in the vaccine and the causal link between it and the damage based on, indeed, the lack of medical family history with this disease and the short time that passed between the vaccination and the occurrence of the disease (par. 13). I think it bears repeating: despite the lack of medical research evidencing this relationship.
Considering that the PLD does not specify what should be considered a sufficient proof of the causal link between the defect and the damage that the consumer needs to establish, it is left to the Member States to decide what evidence is admissible, the level of proof required and the rules for national courts how to evaluate it (par. 25). The established procedural rules should comply with the principle of effectiveness, of course (par. 26), which cannot lead, e.g., to the shift in the burden of proof pursuant to Article 4 PLD or undermine the effectiveness of the strict liability system adopted by this Directive (par. 27). The CJEU confirms that the French procedural rules do not lead to such a shift in the burden of proof but rather just alleviate it by making it easier for consumers to establish the causal link - without having to "produce, in all circumstances, certain and irrefutable evidence of a defect in the product and of a causal link between the defect and the damage suffered" (par. 28). The national court may then conclude that "such a defect has been proven to exist, on the basis of a set of evidence the seriousness, specificity and consistency of which allows it to consider, with a sufficiently high degree of probability, that such a conclusion corresponds to the reality of the situation." (par. 28). Furthermore, the possibility to ban the use of circumstantial methods in proving the causal link would be contrary to the PLD, esp. in situations like here: where the medical research is inconclusive (par. 30), as it would disallow consumers' successful claims of product liability due to excessively difficult burden of proof (par. 31).
Generally then, the CJEU accepts a possibility that national law establishes producers' liability only on the basis of circumstantial evidence. However, it continues to observe that procedural rules may not harm producers by accepting "unjustified presumptions" (par. 34). When would this occur? For example, if national courts are overly rigorous in their application of these evidentiary rules and start accepting irrelevant or insufficient evidence, as a consequence (par. 35). The CJEU goes even further, if national court would draw an automatic presumption on the existence of the defect and of causal link, just because "one or more types of factual evidence were presented together" - this would lead to the disregard of the burden of proof as "the producer could then find itself, even before the courts ruling on the merits of the case had the opportunity to familiarise themselves with the producer’s evidence and arguments, in the position of having to rebut that presumption in order to defend itself successfully against the claim" (par. 36). Therefore, the producer's right to defense needs to be respected.
Concluding, the national court may use circumstantial evidence - if it is sufficiently serious, specific and consistent - to conclude that despite the producer's arguments and evidence presented by him "a defect in the product appears to be the most plausible explanation for the occurrence of the damage, with the result that the defect and the causal link may reasonably be considered to be established." (par. 37).
The CJEU actually addresses the facts of this particular case in the par. 41-42 of the judgment. It seems to advise the national court that in the given case it could be likely to establish a defect and causal link, considering the lack of medical family history of the disease, temporal proximity between the vaccination and the occurrence of the disease, but also the existence of a significant number of reported cases of the disease following such vaccines being administered. This could make it the most plausible explanation for the national court that the administration of the vaccine led to the disease and that the vaccine, therefore, did not offer the safety it should have. But such conclusions have to be drawn "in a fully enlightened manner in each specific case" - the producer's rebuttal being the most important evidence to the contrary.
I think this judgment may lead to quite some disputes. On the one hand, supporters of medical research may feel that the lack of conclusive evidence of the harmful effects of the vaccination should not lead to producers' liability. On the other hand, considering the difficulties consumers would have in acquiring conclusive proof based on medical research, that's contrary, of the harmful effects of the vaccine, the alleviation of the burden of proof might seem reasonable to others.