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Sunday, July 14, 2024
Dr. Brown: Antivirals, antibodies, boostersand worries about the coming winter

Remember this time a year ago, all was relatively quiet several months following the opening first surge of COVID-19 in the winter and spring of 2020.

That early days surge seemed to affect mostly the elderly and those with comorbid conditions. Then everything seemed to settle down by the summer and deep into the fall of 2020.

After the initial scare, the news was encouraging – vaccines were proving to be very effective in clinical trials and would hopefully be available by December and January. It was surreal – an uneasy yet hopeful period set between Thanksgiving and the Christmas and New Year’s festivities.

Then the Alpha (U.K.) variant struck with a vengeance in the latter half December 2020. Alpha proved to be far more catchable and possibly lethal than earlier variants. If that wasn’t bad enough, on the heels of Alpha came another, even more easily transmissible and possibly more deadly variant – Delta.

There was a rush to vaccinate the most vulnerable and health care workers throughout the Western world, but it was too late for most nursing homes – even more died and disturbing trends emerged.

The young and healthy were more vulnerable than earlier days and the anti-vaccination movement began in earnest, fuelled by misinformation on social media and by word of mouth. It was the perfect storm of a surging virus and a significant minority refusing the jab, making herd immunity impossible, if indeed that was ever possible with such a transmissible virus.

Now, I am worried about a repeat. Winter and the festive season are coming again and while most have learned to distance, socialize within their bubbles of friends and families, and wear masks, many are tired of COVID and monk-like living. They want out.

By now, a majority of adults in most provinces are “fully” vaccinated, but we’re learning that’s no guarantee against infections and symptomatic infections occasionally severe enough to warrant hospitalization, as the effectiveness of the mRNA vaccines and probably all other vaccines, begins to wane at the four-to-five-month mark following the second jab.

That’s the lesson from Israel and Qatar in recent months. With well over 80 per cent of its population vaccinated, Israel opened up earlier this year, only for breakthrough cases to surge in the face of waning protection. That’s what the future holds, yearly or perhaps more frequent vaccinations, especially against yet-to-emerge threatening variants.

The earlier we get the rest of the world vaccinated the better off we all will be, although international co-operation on such ventures is hard to achieve. As the science journal “Nature” put it in its Nov. 11 issue, “vaccine effectiveness against infection, hospitalization and death fell considerably after six months, particularly among older people.”

The review added, people who received “a third dose of the Pfizer-BioNTech vaccine were almost 20 times less likely to get seriously ill from COVID-19, and 10 times less likely to get infected than people who had received their second and last dose at least five months before.”

There you have it – the booster shot works and the earlier we receive it, the better, especially for those over 60.

That’s where good news about the arrival of effective antiviral drugs comes in. Given within three days of testing positive for COVID-19 for a five-day course, Pfizer’s drug (Paxlovid) cut hospitalizations by a whopping 87 per cent in early studies.

That’s impressive protection for those who otherwise might have developed serious disease or died. Merck’s oral antiviral drug (Molnupiravir) wasn’t quite as effective as Pfizer’s in early testing, but both antivirals await solid proof of their efficacy and safety.

If the early numbers hold up, they will offer an effective way to fend off the virus for the fully vaccinated whose protection is waning – and the unvaccinated. For Canadians, the stumbling blocks will be supply and cost. Early estimates suggest the cost for a single course of the drug will be several hundred dollars – that is, if we can get it.

Monoclonal antibody infusions have been widely available, at least in the United States, for almost a year and a half, and work provided they are given within a few days of turning positive and/or developing the earliest symptoms. Unfortunately, unlike the antiviral drugs, the antibody drugs require an infusion or when that’s not feasible, by injection. But in Canada, where and how timely?

We learned what works for COVID-19 from a public health perspective – distancing, social bubbles, keeping our hands clean and wearing masks. The same seems to have worked for the common cold and flu for the last two winters as well, and hopefully will do so again this winter as well.

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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