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Friday, February 7, 2025
Dr. Brown: COVID season and the weakness of current mRNA vaccines
With the knowledge that the COVID-19 mRNA vaccine has a short effective period, we've arrived at the current need for repeat vaccinations once or twice a year — each tailored to meet the challenges presented by new variants, writes Dr. William Brown. FILE PHOTO

No surprise — ever since the COVID-19 pandemic began in the winter of 2019-2020, there have been seasonal outbreaks of COVID in long-term care facilities in the Niagara region.

I say no surprise because almost every year since the pandemic began, COVID cases spiked in long-term care facilities at a time when the community was busy with Christmas festivities and shopping.

Seasonal outbreaks are common in long-term care, where vulnerable residents are in close contact with other residents for much of the day and visitors, and sometimes staff, unwittingly bring new mutant versions of the virus into vulnerable communities. This year, most residents received an updated version of the Pfizer or Moderna vaccine in the fall.

The initial wave of COVID in 2019-2020 killed many millions worldwide and some developed long-lasting debilitating symptoms called long COVID. Social distancing and masking were very effective public health measures that helped corral the spread of the virus unit the first vaccines became available in late 2020.

Fortunately, the technology for developing messenger RNA (mRNA) vaccines such as Pfizer-BioNTech and Moderna had been developed well before the pandemic and tailored COVID vaccines were available in less than a year following the onset of the pandemic. That was amazing because, without that “off-the-shelf” technology, vaccine development would have taken several years.

There were other pluses too, such as the development of antiviral drugs such as Paxlovid, which reduced the initial severity of COVID but sometimes was associated with troublesome side effects or symptoms returned after the short five-day course (Paxlovid rebound).

Unfortunately, we soon learned that the effectiveness of mRNA vaccines was less than half a year and, in some instances, as short as three months. The reason for such a short effective period was that this virus mutates frequently and some mutant versions emerged every few months that were capable of evading previously effective vaccines.

This recurring cycle led to the current need for repeat vaccinations once or twice a year — each tailored to meet the challenges presented by new variants. In that respect, COVID vaccines are similar to flu vaccines, which have to be updated every year, but unlike many vaccines that work a lifetime.

But for most healthy young and middle-agers, COVID became a ho-hum affair that few paid much attention to except for seniors, those who are immunocompromised and others at higher risk for COVID.

Like the flu, COVID is now embedded in the population. That means we can expect continuing mutant versions to emerge, including more lethal versions.

The weakness of current mRNA vaccines is that they target mutant versions of proteins in the spike, which, as the last four or more years have shown, continue to develop, some of which are capable of evading recently available vaccinees, thus perpetuating the recurring cycle of mutants and updated vaccines to deal with risky versions.

The answer is to develop a vaccine from the most conserved, least likely to mutate proteins in the COVID virus, not the everchanging proteins of the spike.

Such a proposal for a durable vaccine was made to the National Institute of Health and viewed favourably but not funded before the pandemic and since then has been proposed once more, again with no support by the National Institute of Health.

In recent years, some of the previously well-deserved shine on the National Institute of Health for past efforts has worn off, what with their on-again, off-again highly politized response to monoclonal antibody treatments for Alzheimer’s disease and lack of leadership in developing a more effective vaccine for COVID.

That’s too bad, because a vaccine based on the most stable proteins in the COVID virus from all variants so far in humans and wild animals offers the best chance of developing an effective long-lasting vaccine — instead of the current practice of trying to keep up to date with new mutant versions of the virus.

Given the huge reservoir of the virus in billions of human and wild animal hosts, updating vaccines may not be possible in the future given the strength of the anti-vaccination lobby and anti-vaxxers in the government in the United States beginning this month.

We were lucky with COVID this time around because of the off-the-shelf availability of the technology to create effective vaccines so quickly. But we might not be so fortunate the next time around.

And there’s another issue with COVID – long COVID.

Many people developed chronic fatigue, cognitive impairment and other symptoms which can last for many weeks or even several years with no end in sight. Unfortunately, the cause(s) and effective management of long COVID remain challenges.

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library. 

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