All Occurrences of COVID-19 Within Defined Periods as Proximate Causes under Extension 6: Marlin Apartments Ltd v Allianz PLC

Introduction

In Marlin Apartments Ltd trading as Marlin Hotel Dublin v Allianz PLC ([2025] IEHC 226), the High Court of Ireland (McDonald J) revisited the scope of business interruption cover under Extension 6 of the Allianz policy. Marlin Hotel sued for losses arising from Government-imposed COVID-19 restrictions; Allianz now seeks guidance on how the principal judgment’s logic applies to other insureds. Key issues addressed in this supplemental judgment are:

Whether there is a cut-off date beyond which occurrences of COVID-19 on an insured premises can no longer be said to have caused a later restriction order.
How long after a restriction order a newly diagnosed case may be treated as having occurred before the order (given the incubation period).

Marlin (the plaintiff) has agreed to act as legitimus contradictor to assist the court in answering these questions for the benefit of similarly-situated policyholders.

Summary of the Judgment

The court’s principal findings in this supplemental judgment are:

All undiagnosed or unreported cases of COVID-19 occurring between midnight on 9 December 2020 and the enactment of the Third Restriction Order on 23 December 2020 formed part of the causative chain leading to those restrictions. Cases before 9 December 2020 were objectively excluded once the Minister had relaxed restrictions on 1 and 17 December 2020.
Any person present on the insured premises on the date of the restriction order whose COVID-19 infection is diagnosed within the five-day incubation period after the order must be treated as having been infected before the order and thus part of the causative cohort. The post-order window shortens accordingly if the individual left the premises one to four days before the order.
Claims based on infections diagnosed beyond five days may still be possible—but only if supported by clear evidence of symptoms or test dates that establish infection within 14 days prior to the order, reflecting the outer infectious period.

Analysis

Precedents Cited

Marlin Principal Judgment ([2024] IEHC 550): Held that both reported and unreported cases of COVID-19 were “instrumental” in causing the Third Restriction Order, because the Minister must have considered the full burden of infection (paras. 229–233).
Hyper Trust Ltd v FBD Insurance plc ([2021] IEHC 78): Confirmed that all cases of COVID-19 preceding the first lockdown (15 March 2020) were causative under a pure disease cover clause (no notifiable requirement).
London International Exhibition Centre plc v Allianz Insurance plc ([2024] EWCA Civ 1026, “the Excel case”): English Court of Appeal ruled that a notifiable disease extension requires the disease to be notifiable at the moment of the occurrence, and that unreported cases still count once COVID-19 became notifiable.
FCA v Arch Insurance ([2021] AC 649): Emphasized clear, simple causation principles in COVID-19 BI claims, avoiding undue complexity in proving authority knowledge or precise linkage.

Legal Reasoning

1. Chain-breaking relaxation orders: The Minister’s decision to relax restrictions on 1 December 2020 (S.I. 560/2020) and again on 18 December 2020 demonstrates that cases predating those dates could not have influenced the later Third Restriction Order. The “break” in causation arises because the Minister, having accepted the safety of reopening, must be taken to have discounted earlier cases.

2. Fourteen-day public health metric: The Health Protection Surveillance Centre (HPSC) and NPHET reported trends over rolling 14-day periods, comparing daily counts, 5-day moving averages and cumulative incidence per 100,000. The 23 December report covering 9–22 December 2020 showed a dramatic escalation—clinching the Minister’s decision to reimpose restrictions.

3. Causation window after an order: Medical evidence fixed the usual COVID-19 incubation at 3–5 days, with infectiousness possibly extending to 12–14 days. A simple rule—aligned to the principal judgment and Arch Insurance clarity—is applied: up to five days after a restriction order for cases present on the order date (shortening by one day for each day absence prior to the order).

Impact

This supplemental judgment provides crucial calibrations for insurers and policyholders:

Cut-off date for pre-order infections removed liability uncertainty by pinpointing midnight 9 December 2020 (for the Third Restriction Order), with analogous analysis applicable to future government restrictions.
Post-order diagnosis window simplifies claims handling: insureds need only demonstrate presence on a key date plus subsequent COVID-19 diagnosis within a defined incubation window.
It reinforces the principle that undetected cases count equally to reported cases, preventing insurers from exploiting reporting lags.
Guides resolution of similar BI claims arising from Government-imposed COVID-19 restrictions under “notifiable disease” clauses across multiple jurisdictions.

Complex Concepts Simplified

Notifiable disease: A disease which must by law be reported to public health authorities upon diagnosis or suspicion.
Proximate cause: The primary event or set of events that directly leads to a loss or damage under an insurance policy.
Incubation period: The time between exposure to an infection (e.g., SARS-CoV-2) and the appearance of symptoms—commonly 3–5 days for COVID-19.
14-day cumulative incidence rate: Total new cases per 100,000 population over a rolling 14-day period—used by public health authorities to gauge outbreak severity and guide policy.
5-day moving average: The average number of daily reported cases over a rolling 5-day window—smoothing short-term fluctuations to reveal trends.

Conclusion

Marlin Apartments Ltd v Allianz PLC (Supplemental) crystallizes how Extension 6 business interruption cover responds to COVID-19:

Every occurrence of a notifiable disease on the insured premises—even if undiagnosed or unreported at the time—counts as a proximate cause of subsequent Government restrictions, provided it falls within the relevant causation window.
A clear pre-order cut-off date and post-order incubation window ensure predictability for all parties.
The judgment aligns contractual interpretation with public health practice—using 14-day and 5-day metrics—and promotes straightforward claim protocols.

This decision will shape the resolution of COVID-19 business interruption disputes under notifiable disease extensions and guide insurers in assessing a wider class of policyholder claims.