In previous articles in this series, I have discussed the evidence for/against several Non-Pharmacological Interventions (NPIs) for pandemic influenza mitigation. The first article discussed the similarities between pandemic influenza and COVID-19, and the reasons for examining the evidence for the former in the context of the latter.

Subsequent articles have discussed several of the NPIs listed in the first article.

This concluding article will discuss the following:

• Border closure
• Lockdowns

Border closure

Findings

Eleven studies were included in the systematic review. Of these, two were epidemiological studies, while the remaining were simulation studies.

One study predicted that restricting international air travel would delay the peak of epidemic by up to 3 weeks, but would not affect the attack rate.

International travel restriction is estimated to slow the importation of infections, but would not reduce the duration of epidemic.

Generally, only strict border closures (at least 90% border control) are expected to be effective within small island nations.

It is reasonable to expect that strict border control could affect daily life and have serious economic consequences.

Substantial public resources would be needed, including the provision of public advice and large numbers of staff to restrict cross-border travel.

Border closure applied by nations should be voluntary to the extent possible, and compulsory intervention should be involved as a last resort.

The stigmatization and discrimination of individuals from affected areas should be considered.

For island nations, border closure should be carefully considered as it may affect the supply of essential goods to the population.

In severe pandemics, border closure is technically feasible, and may be most effective in the very early phase of a pandemic.

Notes:

Enforcing border restrictions will be difficult in areas where the border is porous due to geographical reasons, or the presence of forests, for instance.

Borders that are disputed or unstable due to conflict situations may be difficult to control.

In situations where corruption is high, people may bribe their way through borders.

Quality of evidence: There is a very low overall quality of evidence that border closure has an effect on transmission of influenza. Studies in the literature reported or predicted variable effectiveness.

Overall strength of recommendation: Not recommended

Border closure is not recommended unless required by international law or in extraordinary circumstances during a severe pandemic. This is due to the very low quality of evidence, economic consequences, resource implications and ethical implications.

General considerations regarding mitigation measures

Many communitywide disease mitigation measures would be inherently difficult to implement in view of

• The resources required for implementation
• The mechanisms to convince/compel the public
• The duration of time required to enforce the measures- from a few weeks in a small community to many months for the entire country

Measures restricting gathering of individuals in one setting (schools, offices, etc.) will not be effective in preventing transmission of disease if those individuals gather in other settings- markets/ play grounds, etc.

Attempts to enforce prohibition of social gatherings will require considerable resources, and will be difficult to enforce for an extended period of time. Not only will such prohibition cause social disruption, but also serious economic consequences (both short-term and long-term).

Most measures aimed at mitigation disproportionately affect those belonging to economically and socially vulnerable sections of society.