Zain Chagla is an infectious diseases physician and an associate professor at McMaster University.
The calendar is about to turn to 2023 – and yet, incredibly, we are still discussing border restrictions for COVID-19.
Travel bans and strict quarantine rules were first introduced around the world in early 2020, when governments became aware that a novel coronavirus was circulating, and there were few other options to contain the spread. However, it quickly became apparent that significant unaccounted spread to and from other countries was still occurring, and that new variants were emerging. While these measures were debatably effective, one could argue that they were justified early on, when there wasn’t as much information available, as they bought time for vaccines and therapeutics to be developed and distributed to more meaningfully lower risk.
Yet a year ago, in the post-vaccine era, South African scientists alerted the world to the Omicron variant – and the instinct of many governments was to ban travellers from that country. These bans had huge economic ramifications in South Africa, and they even prevented the importation of reagents and other products that were essential for the globally important work of trying to figure out the clinical and molecular characteristics of the new variant.
Now, with the relaxing of strict policies in China, and the subsequent expected rise in infections, border panic has set in again. Testing and quarantining are again being required when travellers from China enter countries such as Japan, India and the United States.
We should know better today.
First, proof of a negative test is no guarantee that someone is not infected; a Canadian study from 2020 showed that more than a third of travel-associated cases test negative initially, before producing a positive result one to two weeks later. PCR tests may be positive for weeks after people are infectious, especially during a period of significant transmission, thereby throwing travellers who pose no threat in limbo.
Secondly, while governments have argued that China’s explosive case growth could lead to a new variant, early sequencing from China suggests that they are dealing with the same variants that other reopened countries have seen. China has never experienced an Omicron wave like the rest of the world did, and so its population may just be experiencing what other countries did a year ago.
Indeed, in March, 2022, Hong Kong’s relaxed COVID-19 policies contributed to widespread transmission of the BA.2 variant that had already been experienced in Canada; the case counts were enormous, and cumulative per-capita deaths during that interval were higher in Hong Kong than Canada’s throughout the entire pandemic. The take-away: the combination of significant urban density, a population that had not been exposed to a variant, waning vaccine efficacy, low vaccine uptake among high-risk groups, and an end to punishing restrictions alone could lead to the spread we are seeing in China.
Even in the worst case scenario – that China’s surge produces a new variant – these travel measures would offer very little protection. By the time Omicron was discovered, it was found to be already circulating in the United States, Canada and Europe undetected, leading to community transmission regardless of restrictions against South Africa. Given our global interconnectedness, a transmissible variant will inevitably spread. While travel restrictions may seem helpful, the reality is even if they are enacted at the start of outbreaks, they may only delay the peak by a few days. Targeting a single country without recognizing this simply allows the virus to come in through other countries.
Finally, if there are minimal domestic measures within a given country, then an individual’s risk of infection is far higher from a local contact than through a traveller. These restrictions thus cause disproportionate pain to those faced with restrictions. China is the world’s most populous country, with a massive diaspora that stretches across the Earth, and travel restrictions will have significant consequences on their ability to see family, conduct business, or potentially even flee a part of the world that was suffering under draconian restrictions.
While more transparency about what’s happening in China would certainly be helpful, there are better ways to monitor the situation than travel testing. Access to molecular testing for individuals returning from China with symptoms would give us the ability to track worldwide cases. Waste water, particularly at airports, can provide a rich mix of virologic information. Finally, improving turnaround times for sequencing COVID-19 strains locally and potentially identifying new ones would offer better local data with which governments can make decisions.
Ultimately, travel restrictions won’t ensure that high-risk individuals are up to date on their COVID-19 vaccines, or that individuals have access to therapeutics when needed. And so, the measures will again be merely performative, allowing us to pretend that we are controlling things when there are many better uses of our time and resources available.