COVID-19 measures can infringe the international human right protection against retrospective law: How to avoid?

It is well established that retrospectivity is against the rule of law and international human rights. It is therefore prohibited by many national laws and international covenants. In simple terms, a law has a retrospective effect if it changes the legal consequence for an act already done.

This article raises the observation for the first time that the COVID-19 legal measures in some jurisdictions seem retrospective at first sight. An obligation-free and lawful act of daily life can suddenly and retrospectively attract a legal obligation to be quarantined, isolated, or tested. The failure to conform with the obligation leads to a fine or even imprisonment. By imposing a new legal consequence for a past act, the law arguably has a retrospective effect. This article will analyse the COVID-19 measures adopted in certain jurisdictions for illustration and comparison. However, despite the measures function similarly, not all of them are actually retrospective. Given that the gist of the rule against retrospectivity is to ensure citizens can plan their lives, it is crucial to provide adequate guidance by properly defining the scope of a law and adhering to the rules of legality. Unlike the UK and the US, the ill-defined measures in Hong Kong and Nova Scotia have retrospective effects.

For clarity, this article acknowledges the underlying public health and public interest considerations of the COVID-19 measures. Instead, the focus is on two points. First, even if a retrospective law can be justified by public health considerations, the retrospectivity, and hence the harm to the rule of law and human rights, can be avoided upon better drafting. Furthermore, the international covenants provide that the rule against retrospectivity is non-derogable even in times of emergency. This means a retrospective measure may not be able to withstand judicial review. Second, there is a practical need to properly define the measures for people to plan their lives, as there may be various reasons (e.g. work-related) why they would not want to be obligated.

What is the rule against retrospectivity?

A widely accepted definition is the one offered by Prof. Elmer Driedger, who defines retrospective law as one which “imposes new results in respect of a past event”. Others define it as one which “creates a new obligation, or imposes a new duty…in respect to transactions or considerations already past”.

It has been noted that “Anglo-American tradition is profoundly hostile to ‘retroactive’ laws”, and American legal philosopher Lon Fuller even commented it as “truly a monstrosity”. A trite aspect of the rule of law is legal certainty, and a retrospective law goes against it because it prevents a person from planning his/her conduct with “reasonable certainty of legal consequence”.

Under international law, Art. 11(2) of the Universal Declaration of Human Rights and Art. 15(1) of the International Covenants of Human Rights prohibit retrospective criminal law. The protection is a non-derogable right. Art. 12 of Hong Kong’s Bill of Rights Ordinance directly replicates the latter.

In Canada, retrospective criminal law is prohibited by s.11(g) of the Canadian Charter of Human Rights, with the rationale of ensuring “citizens are able to foresee the consequences of their conduct so as to be given fair notice of what to avoid”. The rule can, however, be overridden by the legislature, pursuant to s. 33 of the Charter.

In the US, retrospective federal and state laws are prohibited by Art. 1, s. 9, Cl. 3, and Art. 1, s. 10 of the US Constitution respectively.

In the UK, there is “a presumption that statutes are not intended to have a retroactive effect”. The rule against retrospectivity is not absolute though. Although Art. 7 of the European Convention of Human Rights prohibits retrospective criminal law absolutely, the doctrine of Parliamentary sovereignty overrides the non-derogability. Nevertheless, it remains observable that retrospective rulemaking “has few supporters and many opponents”.

The COVID-19 measures

The legal measures for tackling COVID-19 adopted in a number of jurisdictions function very similarly. In the UK, if one has had “close contacts” with a person tested positive for COVID-19, the former will be notified by the government-run program known as NHS Test and Trace and is legally obliged to self-isolate for 14 days. This arrangement is legally based on the Health Protection (Coronavirus, Restrictions) (Self-Isolation) (England) Regulations 2020.

A mechanism similarly based on the notion of “close contact” is adopted in a number of states in the US, such as New York and Maine. The only major difference with the UK approach is that certain US states may require quarantine, instead of mere self-isolation. In terms of the law in the US, the federal law (§264(c), (d) of the Public Health Service Act) only governs situations involving inter-states or overseas travel. The notion of “close contact” is defined by individual states. It is also noteworthy that unlike other jurisdictions discussed, the measures taken usually are looser than other countries – for example, the “NYC Health Department is not currently issuing mandatory isolation or quarantine orders for persons with COVID-19” (NY Guidance, p. 9).

The arrangement is more or less the same in Nova Scotia, Canada. Pursuant to the Order made under the Public Health Act, one has to isolate if he/she has been in “close contact” with a person tested positive (Nova Scotia Order, para. 2.2). Failure to comply leads to a fine or imprisonment under s.71 of the Public Health Act (Nova Scotia Order, para. 16).

Hong Kong’s Prevention and Control of Disease (Compulsory Testing for Certain Persons) Regulation (Cap. 599J) adopts a slightly different approach. First, having “close proximity” is likewise a ground for imposing COVID-19 obligations on a person (HK Regulation, s. 10(2)(b), (c)). Apart from this legal ground, the Regulation also provides for other very generic legal grounds, such as “presence at a particular place” (HK Regulation, s. 10(2)(a)). In other words, the scope of the Hong Kong law is much broader than the other jurisdictions mentioned. Second, instead of requiring isolation or quarantine, the legal obligation imposed is to be compulsorily tested (HK Regulation, s. 10(1)(b)). The failure to comply will lead to a fine (HK Regulation, s. 13) and imprisonment upon further non-compliance (HK Regulation, s. 16).

How are they retrospective?

The above arrangements work very differently from travel testing requirements, of which the latter is prospective. The legal consequence of travel testing requirement stays the same: one is informed beforehand of the obligation to be isolated or tested upon arrival at airports.

By contrast, the above mechanisms work retrospectively. For a person who does an act that is obligation-free at Time X, the act is subsequently made subject to an obligation to self-isolate, be quarantined, or get tested at Time Y. The legal consequence of the act at Time X is changed retrospectively (in other words, a new obligation is imposed at Time Y for the act done at Time X). This accords exactly with Prof. Andrew Palmer and Prof. Charles Sampford’s definition that “[r]etrospective legislation can be seen as altering the future legal consequences of past events” (p. 220).

Dining with friends, working with colleagues, studying with schoolmates can all involve “close contacts”. They are not wrongful acts intentionally or negligently done to get exposed, such as not wearing masks. The point is that the rule against retrospectivity becomes highly relevant because the includable activities are normal acts of daily life. The possibility of “expand[ing] the range of activities that are covered by an existing criminal offence” undermines citizens’ ability to plan the legal consequences of their daily activities.

The NHS Test and Trace in the UK will contact individuals who have had close contacts, so is the same in the US (e.g. by the NYC Test & Trace Corps, a program co-led by the NYC Department of Health and Mental Hygiene).

By contrast, Hong Kong and Nova Scotia impose obligations by way of public notice. The public notice will list a number of exposed locations, such as restaurants, and persons who have visited there at a specified time and/or date will have to comply with the suddenly-imposed obligations.

Not all of them are actually retrospective, despite functioning in a similar manner

Despite the above mechanisms seem to function retrospectively, not all of them are actually retrospective upon closer analysis. The gist of the rule against retrospectivity is to ensure people can plan the legal consequence of their acts.

On this understanding, a person can prevent subsequent obligations by avoiding “close contacts”, and the measures are therefore not retrospective. The UK and the US have clearly defined what amounts to “close contact”. In the UK, the Regulation explicitly defines “close contact” as including, inter alia, (1) “having face-to-face contact with someone at a distance of less than 1 metre” and (2) “spending more than 15 minutes within 2 metres of an individual” (UK Regulation, s. 5).

In the US, the guidance too helpfully specifies the distance and duration. For example, in New York, “a close contact is defined as someone who was within 6 feet of an infected person for a cumulative total of at least 10 minutes over a 24-hour period” (NY Guidance, p. 10).

However, Hong Kong and Nova Scotia are different because there is no way one can avoid “close contact”. In Nova Scotia, the legal Order does not specify the definition of “close contact”. Instead, the definition is merely included in a recommended governmental guidance (Nova Scotia Interim Guidance: Public Health Measures of cases and contacts associated with Novel Coronavirus (COVID-19), dated 19 November 2020). Whilst not taking the form of law is not problematic, the guidance too fails to define it properly. “Close contact” includes (1) “close physical contact without protective equipment”, “close prolonged contact” or “direct contact with infectious body fluids” (Nova Scotia Guidance, p. 8).

Unlike the detailed definitions adopted in the UK and the US, it does not specify the distance and time numerically. In other words, it is uncertain what “close” and “prolonged” entail. Moreover, it even states explicitly that the duration cannot be specified because “[a]vailable evidence is insufficient for precision on defining the length of time required for prolonged exposure” (Nova Scotia Guidance, p. 8).  With such scarce guidance, there is no way a person can confidently avoid “close contact” and plan the legal consequence.

In Hong Kong, the notion of “close proximity” is not defined at all – i.e. with even less guidance than Nova Scotia. Furthermore, the legal measures contain questionably broad grounds such as “presence at a particular place” (HK Regulation, s. 10(2)(a)). This raises questions of uncertainty over whether a fleeting presence will be included.

Reviewing the public notice in Hong Kong and Nova Scotia, they impose obligations on those who have visited the listed restaurants. This means that even if one merely purchased takeaways, or even simply visited the stores to have a look without dining in or to take a sample menu, he/she is still subject to the obligations. The measures failed to differentiate the possibility that a visit can be transient without the need to take off a mask.

Such an undifferentiating, broad-brush approach apparently allows the arbitrary application of the notion of “close contact” or “close proximity” (and for Hong Kong, also the notion of “presence at a particular place” criteria).

Concluding suggestion: The fine details matter

To avoid retrospectivity, it is essential to provide ample guidance for people to plan the legal result of their acts. The trite maxim on the principle of legality, nulla poena sine lege certa, comes into play, which requires the law to be certain and properly defined. The notion of “close contact” or “close proximity” (for Hong Kong, also the concept of “presence at a particular place”) should be properly defined with sufficient details, in terms of the (1) duration, (2) distance and (3) whether a mask is used, as is done in the UK and the US.


Martin Kwan is a researcher at the OBOR Legal Research Centre.

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