Historical Cases of Adverse Drug Reactions: Legal Lessons from Thalidomide to COVID-19 Vaccines

In March 2025, the Hong Kong Department of Health confirmed 12 new cases of myocarditis and pericarditis linked to mRNA COVID-19 vaccines administered under the Government Vaccination Programme, bringing the total reported adverse events following immunisation (AEFI) to over 15,000 since the programme’s launch in February 2021. This data, published in the Hong Kong Adverse Event Following Immunisation Report (First Quarter 2025), has reignited a long-standing legal and regulatory question: how should Hong Kong balance the public health imperative of mass vaccination against the liability risks borne by manufacturers, distributors, and the government itself? The answer lies not in a single ordinance, but in a century of drug-safety failures—from thalidomide to the present—that have shaped the legal frameworks governing adverse drug reactions (ADRs) in common-law jurisdictions. For Hong Kong litigants-in-person, HR professionals managing workplace vaccine mandates, and compliance officers navigating product liability claims, the historical trajectory of ADR litigation offers procedural and doctrinal lessons that remain directly relevant today.

The Thalidomide Precedent: Strict Liability and the Birth of Consumer Protection

The 1960s Catastrophe and Its Legal Aftermath

Thalidomide, a sedative marketed in 1957 by the German company Chemie Grünenthal, caused an estimated 10,000 cases of phocomelia—a severe limb deformity—in children born to mothers who took the drug during pregnancy. The legal response in Hong Kong was indirect but consequential. The United Kingdom’s enactment of the Consumer Protection Act 1987, which introduced strict liability for defective products under Part I, influenced Hong Kong’s own product liability regime. The Hong Kong legislature adopted the Supply of Services (Implied Terms) Ordinance (Cap. 457) in 1994, but it was the Control of Exemption Clauses Ordinance (Cap. 71) that provided the first statutory foothold for claimants. Section 8 of Cap. 71 renders void any contractual term that excludes or restricts liability for death or personal injury resulting from negligence. For a litigant-in-person in Hong Kong today, the thalidomide lesson is procedural: the burden of proof in a negligence claim rests on the claimant to show that the manufacturer failed to exercise reasonable care—a standard that, in practice, requires expert evidence and access to internal testing data.

The Hong Kong Adaptation: Common Law Tort and the Caparo Test

The House of Lords’ decision in Caparo Industries plc v Dickman [1990] 2 AC 605 established a three-part test for the duty of care: foreseeability of harm, proximity of relationship, and whether it is fair, just, and reasonable to impose liability. The Hong Kong Court of Final Appeal applied this test in Lo Siu Lan v The Hong Kong Housing Authority (2005) 8 HKCFAR 362, confirming that the Caparo framework governs negligence claims in Hong Kong. For ADR cases, this means a claimant must demonstrate that the drug manufacturer owed a duty to the end-user, that the duty was breached by failing to warn of known risks, and that the breach caused the injury. The thalidomide litigation never reached a final judgment in Hong Kong, but its legacy is the Consumer Goods Safety Ordinance (Cap. 456), enacted in 1995, which imposes a general duty on manufacturers to ensure that goods are reasonably safe. Section 6 of Cap. 456 provides that a contravention is not of itself a criminal offence, but it may be relied on as evidence of negligence in civil proceedings.

The DES Disaster: Market-Share Liability and Causation Challenges

The 1970s U.S. Litigation and Its Limited Reception in Hong Kong

Diethylstilbestrol (DES), a synthetic oestrogen prescribed between 1947 and 1971 to prevent miscarriage, caused vaginal clear-cell adenocarcinoma in the daughters of women who took the drug. The landmark California Supreme Court case Sindell v Abbott Laboratories (1980) 26 Cal. 3d 588 introduced market-share liability: each defendant manufacturer was held liable in proportion to its share of the DES market, even if the plaintiff could not identify which specific manufacturer produced the drug taken by her mother. The Hong Kong courts have not adopted market-share liability. In Kong Yun Ching v The Incorporated Owners of Kwun Tong Garden Estate [2000] 2 HKLRD 319, the District Court declined to extend joint-and-several liability beyond established categories. For a Hong Kong claimant in an ADR case, the procedural rule is clear: you must identify the specific manufacturer. The Limitation Ordinance (Cap. 347) provides a six-year limitation period for tort claims, running from the date the cause of action accrued. Section 27(1) of Cap. 347 preserves the court’s discretion to extend time in personal injury cases, but only if the claimant can show that the material facts were outside their knowledge until a later date.

Causation and the “But For” Test

The Hong Kong courts apply the “but for” test for factual causation. In Chan Pui Ki v Leung On [1996] 2 HKLR 401, the Court of Appeal held that the claimant must prove, on a balance of probabilities, that the defendant’s breach caused the injury. For ADR cases involving multiple potential causes—genetic predisposition, environmental factors, or other medications—this presents a high evidentiary hurdle. The DES litigation in the United States led to the development of the “increased risk” doctrine, but the Hong Kong Court of Final Appeal in Wong Kwok Keung v The Incorporated Owners of Greenfield Garden (2008) 11 HKCFAR 650 confirmed that the standard remains the balance of probabilities. A claimant who can show only a 40% probability that the drug caused the injury will fail.

The Vioxx Withdrawal: Mass Tort Mechanisms and the Role of ADR

The 2004 Withdrawal and Its Procedural Impact

Merck & Co. withdrew rofecoxib (Vioxx) from the global market in September 2004 after a study showed a doubled risk of heart attack and stroke. The resulting U.S. litigation involved over 50,000 individual claims, consolidated into a multidistrict litigation (MDL) before Judge Eldon Fallon in the Eastern District of Louisiana. Hong Kong has no MDL mechanism. The High Court Ordinance (Cap. 4) provides for consolidation of actions under Order 4, rule 9 of the Rules of the High Court, but this is discretionary and rarely used for mass torts. The District Court Ordinance (Cap. 336) limits the District Court’s jurisdiction to claims not exceeding HKD 3 million, meaning most ADR-related personal injury claims proceed in the Court of First Instance.

The Role of Mediation in Hong Kong

The Vioxx settlement—USD 4.85 billion—was achieved through a court-supervised mediation process. Hong Kong’s Mediation Ordinance (Cap. 620), effective 1 January 2013, provides a statutory framework for mediated settlements. Section 3 of Cap. 620 defines mediation as a structured process in which one or more impartial individuals assist parties to negotiate a resolution. For an HR professional managing a workplace vaccine dispute, the Employment Ordinance (Cap. 57) does not mandate mediation, but the Labour Department’s Code of Practice on Employment Practices for the Prevention of COVID-19 (2022 edition) recommends mediation for disputes arising from vaccine mandates. The Arbitration Ordinance (Cap. 609) offers an alternative for commercial parties: section 20 provides that an arbitration agreement may be in the form of a clause in a contract, and section 23 permits the tribunal to order interim measures, including the preservation of evidence.

COVID-19 Vaccines: The New Frontier of ADR Liability in Hong Kong

The Government Vaccination Programme and the Indemnity Framework

The Hong Kong Government’s COVID-19 Vaccination Programme, launched in February 2021, operates under a no-fault compensation scheme. The COVID-19 Vaccination Programme – Compensation for Injury Arising from Vaccination (Cap. 599K, Subsidiary Legislation) provides a fixed-sum payment of HKD 250,000 for death and HKD 300,000 for specified serious injuries, such as myocarditis or anaphylaxis. Section 3 of the scheme requires the claimant to prove that the injury was caused by the vaccine on a balance of probabilities—the same standard as a common-law tort claim. As of the First Quarter 2025 report, the scheme had received 1,402 applications, of which 872 were approved. The scheme expressly excludes liability for negligence or breach of statutory duty, meaning a claimant who accepts the fixed sum waives the right to sue.

Product Liability and the Manufacturer’s Defence

The Consumer Goods Safety Ordinance (Cap. 456) applies to vaccines as “consumer goods” under section 2. Section 6 imposes a duty on the manufacturer to ensure the goods are reasonably safe. However, the defence of “development risks” under section 6(3)(b) of the Supply of Services (Implied Terms) Ordinance (Cap. 457)—that the state of scientific knowledge at the time of supply was not such that a reasonable manufacturer would have discovered the defect—may apply. For a compliance officer at a pharmaceutical distributor, the procedural takeaway is this: maintain all records of regulatory approvals, batch testing, and adverse event reports for at least 10 years, as the limitation period under Cap. 347 may be extended if the injury is latent.

Actionable Takeaways for Hong Kong Professionals

1. For litigants-in-person: file your claim within six years of the injury, or within three years of discovering the causal link, whichever is later, under section 27(1) of the Limitation Ordinance (Cap. 347).
2. For HR professionals: document all vaccine mandate communications and employee refusals, as the Labour Tribunal may consider failure to follow the Code of Practice as evidence of procedural unfairness under section 32A of the Employment Ordinance (Cap. 57).
3. For compliance officers: ensure that your product liability insurance policy covers “development risks” exclusions, as the Hong Kong courts have not yet ruled on the applicability of this defence to vaccines.
4. For all parties: consider mediation under Cap. 620 before issuing a writ, as the court may order costs against a party that unreasonably refuses to mediate, per the Court of Appeal’s guidance in Hyundai Engineering & Construction Co Ltd v Vigour Ltd [2004] 2 HKLRD 1.
5. For those contemplating arbitration: include an express arbitration clause referencing Cap. 609 in any supply agreement with a vaccine manufacturer, as section 19 of Cap. 609 provides that the tribunal may award costs on an indemnity basis if a party fails to comply with a pre-arbitration mediation requirement.

This does not constitute legal advice. Consult a solicitor for your specific case.