Closing borders to all foreign travelers will have “significantly slowed” the spread of COVID-19, unlike partial closures targeting countries where outbreaks were reported, a measure that had little or no effect.
This is the main conclusion reached by researchers from York University, Toronto, who analyzed the effects of comprehensive and targeted shutdowns during the first wave of the pandemic in February and March 2020.
The results of the study vary according to whether one analyzes the spread on a global or domestic scale in countries which have closed their borders completely or partially and according to the countries themselves, specified the main researcher, Mathieu Poirier, during an interview with The Canadian Press.
Assistant professor in social epidemiology and holder of the institution’s Global Health Equity Research Chair, Mr. Poirier points out, however, that the results, published Monday in the journal PLOS Global Health, are conclusive overall, although ‘they require important nuances.
Total closure vs targeted closure
His team analyzed available information from 166 countries to compare coronavirus transmission data before and after the partial and full shutdown to that of countries whose borders had remained open. On a global scale, “the total closure (of borders) slows down global and internal transmission”, he concludes.
In stark contrast, “we haven’t seen any significant declines (in spread) for targeted shutdowns globally. »
The results at the domestic level, that is to say within countries, vary slightly, however. We note that both total and partial closures had an impact on reducing the spread, but that total closures were more effective.
Partial closures, on the other hand, were effective when implemented early and targeted more countries: “Targeting more countries has proven more effective than just targeting higher-risk countries. . In other words, the logic is respected: the wider the border closure, the more effective it is.
The researchers’ work confirmed a reality already noted in the past, specifies Professor Poirier: “It was not the first time that we had tried to target countries and it was not the first time that we found that it was not effective. »
Wrong targeting
The reason, he says, is very simple: what we think we know does not usually correspond to reality. “Even if you think you know where there is a hot spot or an outbreak is going on, it is very likely that it is also happening in other countries where it is not as obvious, where we reports less well (epidemiological data). This is exactly what has been seen in the shutdowns targeting southern African countries with Omicron. »
Moreover, he adds, this targeting, in addition to being ineffective, is harmful: “I want to emphasize the fact that the targeted closures were not only less effective at the domestic level and at the global level, but that they punish countries that openly and transparently report outbreaks and that this can lead to a less effective and slower global response to this kind of threat. It can also have real economic and social consequences for the targeted country. »
Effective in Canada
Canada is no exception to the rule, but Mathieu Poirier points out that Ottawa was quick to switch to complete sealing: “Canada has experienced a rapid transition from targeted countries to total closure. The total shutdown implemented in Canada was followed by a significant reduction in COVID transmission. »
In any case, it should be noted that the researchers do not give precise figures on this reduction: “Our level of confidence is not high enough to go so far as to quantify these reductions. On the other hand, it is very high when it comes to asserting that these are significant reductions. »
However, even if a country implements a total shutdown, “it might have no effect because it’s not strict enough, that unfortunately international traffic still enters, that the country does not have the means screening or implementing appropriate public health measures. »
A total closure, “this is not a guarantee”, he warns.
Legal closures or not?
The study also raises, without however resolving it, the question of the legality of these border closures, partial or total. Although countries are sovereign in controlling their borders, a pandemic refers decisions that have international implications to the International Health Regulations (IHR) which are legally binding on the World Health Organization (WHO) and 196 countries, including Canada.
One of the principles of IHR is that a measure should not be more restrictive than necessary and that decisions should be based on science. However, argues the researcher, “with a pandemic spreading so quickly, we do not have reliable information when making these decisions. And in this case, he adds, at the time of closing the borders, “there was no scientific data to say whether these closures worked or not. »
other options
According to Mathieu Poirier, it is not at all impossible, precisely, that these closures were illegal under the RSI: “There were better options for several countries, although the complete closures were effective, as we know now. »
Some countries, for example, could have imposed strict quarantines and other heavy-handed internal public health measures to control transmission just as well as shutdown. “It would have been less disruptive and, therefore, a better measure. »
At the same time, he says, there are countries that have been able to benefit from the additional time offered by the slower spread caused by a total shutdown, including countries with less international traffic and fewer resources to fight domestic spread. effectively: “There are definitely benefits to getting more time to prepare internally. »
A gray area
International discussions are underway to try to refine the laws governing these decisions, especially on the basis of data such as those provided by researchers at York University. “We need to build this data so that in the future countries can say: according to the available science, there are certain situations where closing the border is legal and defensible. »
However, like everything else about COVID-19, this virus that scientists are still struggling to understand, the legal aspects also give experts a hard time: “The legality changes according to science. It was a gray area and it continues to be a gray area,” sighs the researcher.