The last of Ontario’s COVID-19 mask mandates — which have still been in effect in settings like hospitals and public transit — are scheduled to expire on June 11. While border protocols, such as random testing, have been extended at least until the end of June, long lineups at Toronto’s Pearson International Airport are fuelling calls to lift them.
COVID-19 is still with us, but just as the virus has changed since 2020, so have our personal and public reactions toward it. As personal risk assessment becomes more important with fewer and fewer public health mandates, there are good lessons to be learned from how our immune system works.
In immunology, the way a threat — such as a virus — is presented to the immune system matters as much as the threat itself. The same can be said of public health messaging: its effectiveness rests on how it’s presented.
The immune system is a diverse collection of tissues, cells, and molecules that — at its core — specialize in highly co-ordinated communication. Antibodies and T-cells are key in assessing how the immune system responds to a novel virus, like SARS-CoV-2. To recognize and respond to the threat, those cells need specific messages clearly presented in specific ways. This leads to tailored protective actions, including those carried out by antibodies.
Antibodies act as specialized flags that not only identify viral particles so the immune system can find them, but also block those particles from infecting healthy cells.
Parts of the immune system remain fairly constant, but other parts are adaptive and can be tweaked in response to threats. T-cells and B-cells are highly sensitive to this, and shape adaptive immunity.
To make antibodies, B-cells must be able to recognize a fragment of the virus. A special class of T-cells called helpers must present the virus fragment to the B-cell in a very specific way. This leads to antibody-mediated protection.
Likewise, for a different class of T-cells — called killers — a small piece of the virus needs to be shown in a slightly different way. This specific presentation of the viral fragment is crucial to generating adaptive immunity, which then mobilizes the process of destroying the virus.
This is precisely what vaccines are designed to enable, but in a safe context avoiding actual virus exposure. Successful immune response gives us an army of trained killers that only recognize that one unique virus fragment.
Clearly, details matter to the immune system. Change what that virus fragment looks like (mutate it), and that same trained immune system may let the virus slip by and need more guidance to re-adapt. And it does adapt. Continuously.
The same concept applies in public health messaging and science communication. When the context changes, so should the strategy and the messaging to the public.
Over the course of the pandemic, its context has changed as the virus has changed. The more is learned about the virus, the better the public health messaging can be tailored. If that is done well, it can help minimize the impact of the virus on communities, at least in theory.
In early 2020, local viral spread was low and our understanding of transmission was nascent. Public health advice reflected this. Today, community viral spread is high and we understand its transmission routes. Public messaging should have adapted to this knowledge. Instead, masks and other protections have been dropped.
Paramount from a public health strategy perspective, we have learned that this virus is mostly spread via airborne routes, in the same way that cigarette smoke moves and lingers. Picture it just like that!
But what hasn’t been done well is shaping public understanding of this to inform a strong mental model that can be applied to assess personal and public risk. We know mask quality matters, with K/N95 as the best choice. We know indoor air ventilation and filtration matters. And we know that vaccines work to train your immune system, with three or four doses being ideal in this particular context.
Adapting to COVID-19
As the sixth wave waned in Canada, the message was that it was time to try “living with COVID-19.”
This shift in messaging has consequences. It accepts that recurrent waves of the virus will circulate, with the accompanying impact on our personal and community health. This includes the unknown impact of emerging subvariants and future novel variants. To minimize those risks, there is a need to not just surrender to living with the virus and hope for a return to normal, but to adapt to living with COVID-19.
Despite the effectiveness of current vaccines, vaccination will not solve this on its own. More tools are on the way in the form of variant-tailored, pan-coronavirus and mucosal vaccines (nasal sprays) and antivirals.
The path back to ‘normal’
The path back to a sense of normal doesn’t involve ignoring the threat, and letting it pass, hoping the damage will be manageable. Rather, much like the immune system depends on clear communication to adapt, the path back to normal may depend on public education about vaccination, risk mitigation — such as knowing when it’s best to mask and which mask to choose — and policy development to improve indoor air quality.
Our immune system adapts to a changing virus by showing our T- and B-cells what has mutated in the latest variant. It learns from the most recent and best available evidence, and creates the best-prepared army of precision antibodies and killer cells. We must enable this at the public response level too.
As individuals, we are the B- and T-cells of our community immunity right now. We need clearly presented strategic information to recognize and precisely assess the threat. As the pandemic continues — and yes, it does continue — public and personal behaviour needs to evolve with the changing pandemic context, with clear public health messaging and infrastructure action.
Like the pieces of immune system, we are all in this together, not individually.
Adam J. MacNeil receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC), New Frontiers in Research Fund (NFRF), Canadian Institutes of Health Research (CIHR), Mitacs, Ontario & the Canada Foundation for Innovation (CFI).