By Peter Chow
COVID-19 caused the nation to shut down and wreaked havoc on everyone’s daily lives. International travel has been halted, restaurants and businesses have been closed, and large gatherings and celebrations have been forced to be postponed or canceled. After six months of quarantine and social distancing, however, people are developing pandemic fatigue.
Over 150 candidate vaccines for COVID-19 are currently being investigated in different phases of study. With a few entering Phase 3 studies, there have been talks of the COVID-19 vaccine being the “magic solution” and “magic cure” for ending the pandemic. Unfortunately, there are numerous factors that impact the efficacy of the vaccine and the extent of impact the vaccine would have on the pandemic.
Vaccine efficacy varies. Some vaccines, such as the polio vaccine, has been nearly 100 percent effective. The annual influenza vaccine, however, is only about 30 to 60 percent effective, according to the CDC.
Those most at risk of COVID-19 are least likely to respond to a vaccine.
Emerging infectious diseases like COVID-19 can be a double-whammy for older adults. Aging depletes the arsenal of adaptable T-cells, as the thymus gland, the source of T-cells, fills with fatty tissue. T-cells help the immune system mount defences such as antibodies. As a result, our immune systems become ill-equipped to fight off new viruses.
Vaccines provide instructions for our immune system, which T-cells help pass along. By age 40 or 50, the thymus has exhausted most of its reserve of the kind of T-cells that can learn to recognize unfamiliar pathogens—and ‘train’ other immune cells to fight them.
Vaccine makers have gained some experience with “immunosenescence” – the dysfunction of the aging immune system – in dealing with influenza. Older people are more susceptible to it, and flu vaccines typically protect them less.
To overcome that, vaccine giant Sanofi Pasteur, created an influenza vaccine called Fluzone for people 65 and older that contains four times as much immune-stimulating ‘antigen’, a molecular component of a pathogen that can trigger the body to make protective antibodies. A study found that the high-dose version was 24 percent more effective than the regular dose.
Another way to boost the efficacy of flu immunizations for older people is to use adjuvants – added ingredients that make vaccines stimulate the immune system more strongly. The Fluad vaccine, for instance, contains an adjuvant which is partially derived from squalene, a natural oil produced by the skin and by plants.
Adjuvants have been used for around a century in vaccines, not just for flu or for older people. But even tried-and-tested ones have been framed as dangerous by anti-vaccine crusaders.
To make matters worse, immunosenescence isn’t the only challenge facing researchers trying to design COVID-19 vaccines for older people. There’s increasing evidence that many seniors have another problem: their immune system is already preoccupied with fighting viruses that cause lifelong infections once they enter the body, such as the typically benign cytomegalovirus (CMV).
When you look at the elderly, 20 percent of the immune system is sometimes directed toward CMV. Suppressing all these viruses comes at a cost.
Scientists call it “inflammaging”: the immune system is essentially stuck in an inflammatory state. That might make it harder for the body to detect a new pathogen like COVID-19 – or to get stimulated by a vaccine against it.
It’s essentially like being in a room with lots of noise and someone yells help – you won’t hear it.
Even if there was a vaccine that was effective, who would be getting the vaccine? To mass-produce and vaccinate every individual requires extensive resources and time. Who would get the vaccine first? Healthcare workers? Those with numerous medical comorbidities? How about those living in shelters with limited or no access to healthcare?
Another limitation is that not everyone is willing to receive the vaccine. With the expedited research process, the large amount of misinformation and conflicting information about COVID-19, many people have been losing faith in the science/medicine and do not feel safe receiving a COVID-19 vaccine yet. Furthermore, there will likely be a group of anti-vaxxers who will not take the COVID-19 vaccine.
Only 57% of Americans say they would get a COVID-19 vaccine if it were available today, according to a national survey.
Regarding when respondents planned on getting a vaccine once it was available, the most popular timeframe was a few months after release, at 30%. Just 13% said they would get it immediately; 16% said they would wait a few weeks; 18% said they would wait at least a year; and 23% said they would not get a vaccine at all.
A Statistics Canada survey found nearly one-quarter of respondents unlikely whether they would get a COVID-19 vaccine.
76 per cent of respondents in the Stats Canada survey indicated they would likely get inoculated. Yet 14 per cent said they were very unlikely to do so. 10 per cent were definite no’s.
About one-quarter of respondents said they did not consider it necessary to get the vaccine while about 13 per cent indicated they did not believe in vaccines at all.
More than one-third of Canadians said they would likely just wait until the vaccine seemed safe.
Lastly, the immunity conferred through immunization may not last. Some studies show a decline in IgG antibodies within months after contracting SARS-CoV-2, and there are case reports of reinfection. Furthermore, historically, immunity for such viruses have failed to produce long-lasting antibodies and immunity.
There are numerous roadblocks and barriers — vaccine efficacy, the ability to mass-produce and vaccinate everyone, and the questionable and unknown immunity conferred from the vaccine — that prevent a COVID-19 vaccine from being the “magical solution” to end the pandemic.