Opinions
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Pandemic's third wavecalls for intensive public health action |
by Dr. Rey Pagtakhan
Until recently, Canadians were seeing the horizon of a return to a near-normal life. Four COVID-19 vaccines have been authorized for emergency use, nationwide vaccination has commenced, and COVID-19 cases and deaths have become preventable. The pandemic beast would soon be tamed and a sense of optimism was high.
In less than a month since spring 2021 began, a resurgence of new cases, increased utilization of hospital beds and intensive care units, and more deaths have validated the presence of the third wave. It is more severe in Ontario, Quebec, British Columbia and Alberta due to the increasing dominance of variants of concern.
Update on human toll and hospitals
In the past week, hospitalizations rose 26 per cent and utilization of ICU beds rose 19 per cent. As of April 13, the total number of COVID cases in Canada was 1,078,482 with a total of 23,336 deaths, according to the Johns Hopkins University Coronavirus Tracker. The daily average of 8,621 cases and 36 deaths for the preceding week made for an increase of 33 per cent and 28 per cent, respectively. Except for New Brunswick and the territories, the increases in the human toll were spread across the country – the red flag for a third pandemic wave.
Magnitude of COVID-19 variants
Referring to the third wave now in “full bloom,” the Globe and Mail editorial of March 31st said: “A March that came like a lamb and went out like a lion…the country is effectively in a new pandemic, as new variants displace our reliable old.”
The Public Health Agency of Canada and provincial health authorities have been tracking the number of cases of these three variants nationwide: B.1.1.7 – 33,720; P.1 – 1,218; and B.1.351 – 357, as of April 12th. The highest numbers were in Ontario (16,761), accounting for about 70 per cent of the province’s total cases, and in Alberta (10,770); less in British Columbia (4,111) and the rest of the provinces. These occurrences parallel the severity of the resurgence seen among the provinces. The doubling rise in the P.1 variant, first detected in Brazil, in British Columbia, Ontario and Alberta is extremely concerning because of its propensity to spread quickly.
These variants of concern are more formidable foes than the original version of SARS-CoV-2. They carry a 63 per cent higher risk of hospitalization, 103 per cent higher risk of intensive care unit admissions, and a 56 per cent greater risk of death. However, whether they make people sicker than the original strains of the virus is not settled. Their impact on the healthcare system is enormous and fast, creating real “moral distress.”
Younger people in their 20s, 30s, and 40s have been more affected now. Substantial numbers of outbreaks with B.1.1.7 have occurred in schools. The risk of this variant to children and their families may also be due to an inability of children to maintain social distancing and masking, and to avoid contact sports. Schools and daycares are obvious situations for close contact transmission and the subsequent spread at homes. It is a challenge to maintain in-class learning and meet the increasing demand to reopen schools.
Variants have a selective advantage
The B.1.1.7 and the B.1.351 variants bind to the ACE2 receptor-binding domain with a two-fold and five-fold greater affinity, respectively. This greater affinity helps explain why these variants are more transmissible and transmit for longer periods of time. The B.1.1.7 variant also carries a so-called “deletions” type of mutation, because it eliminates part of the genetic code and, as a result, helps this variant to escape antibodies produced during the body’s immune response to an infection. Moreover, it can cause commercial testing kits to give false negative results by failing to detect its spike protein gene. A looming new risk is the identification of so-called double mutants.
What forces could have led to the resurgence?
A number of forces may have been at play: 1. large gatherings at super spreader events, 2. vaccination has not been optimal, 3. letting one’s guard down after receiving the first vaccine dose, 4. premature lifting of public health restrictions and then delaying their re-imposition, 5. conflicting messaging over vaccines 6. distrust of leaders. 7. inconsistent enforcement of existing health measures, and 8. pandemic fatigue. It is not clear how much each of these possible forces contributed to the resurgence. What is clear is the devastating human toll the variants of concern have exacted with their ability to spread and to affect the younger generations. Knowing these forces could help inform the design of an exit plan.
Outline of exit plan from the third wave
World pandemic expert Dr. Anthony Fauci, Chief Medical Adviser to US President Biden, speaks of two key things for a possible exit, “A: keep pushing and doubling down on public health measures; and B: do whatever you can to get as many people vaccinated as quickly and as expeditiously as possible.” (CNN News, April 3, 2021)
Status of public health guidance
Ostensibly, our hope to have every Canadian vaccinated (before a third wave) has vanished. The challenge now is to comply with safety restrictions until our vaccine rollout keeps pace with the exponential increase in the number of variants. Keeping the greatest distance, avoiding congregate gatherings, particularly indoors with poor ventilation, washing (not merely rinsing) our hands with soap and water for at least 20 seconds, or using a hand sanitizer, avoiding touching one’s face, and wearing a best-fitting face mask – these measures cannot be overemphasized.
Public Health Canada has advised against recreational travels within the country. Lockdowns and other more restrictive safety measures have been declared in several provinces.
Current vaccination status
Canada Research Chair of emerging viruses and assistant professor at the University of Manitoba, Jason Kindrachuk, said recently on CBC News, “We have a lot of virus moving around the country and escalating very, very quickly…Vaccinations are certainly starting to pick up, but we’re nowhere near where we need to be to get this thing under control.”
There is some good news
As of April 13, a total of 8,583,763 vaccine doses have been administered to Canadians, reflecting a vaccination of 20.41 per cent of the total population with at least one dose (7,755,670) and 24.57 per cent of the 16 years and older eligible population.
About 2.15 per cent of the population has received the two doses. The lowest number is in British Columbia, 1.71 per cent, and only slightly higher in the other provinces – from 1.86 per cent in Newfoundland and Labrador to 4.96 per cent in Manitoba. The numbers are much higher in the three territories – from 24.09 per cent in Nunavut to 36.38 per cent in the Yukon.
That a fifth of the total population or a quarter of the eligible recipients has received one dose is a remarkable achievement. Especially remarkable considering that Canada depends on imported vaccines for its supply and there were disruptions in the preceding two months. These figures place the country third among the G-7 and G-20 nations of the world.
It is also good news that the available vaccines protect children age 12 to 15, for whom application for emergency use authorization may be filed soon. In addition to protecting them directly, children comprise a significant segment for development of herd immunity.
Moreover, Pfizer has been consistently delivering more than one million doses weekly for more than a month now, and is expected to continue. Moderna has tried to catch-up with its deliveries, too. Over the next three months, Canada expects delivery of at least 22 million doses; enough to vaccinate nearly all adults come Canada Day.
Our success to date does not mean we should not be open to more intensive and flexible modes of vaccination. Naturally, we all worry about the remaining 28.5 million people waiting to be vaccinated with at least one dose – essential workers at meat processing plants, warehouses and transport companies who cannot work from home, and others in similarly difficult situations. Let us all be conscious that protecting many more of our fellow Canadians with their first dose also protects us all in the community as a whole. I am confident our public health officials and provincial and territorial governments are aiming to vaccinate their populations as “quickly and as expeditiously as possible.”
How the human body responds to SARS-CoV-2 infection
Each SARS-CoV-2 particle has the characteristic spikes of protein on its surface that look like a crown. These protein-spikes help the virus attach to the ACE2 receptor proteins found on the outer wall of human cells, and then enter the host cell, make more copies of themselves, which triggers infection and causes disease.
In response to the virus infection, the body forms Y- shaped antibodies that bind to the spikes, marking them for destruction by the simultaneously activated T-cells.
How COVID-19 vaccines work
Using different approaches, the four vaccines – Pfizer, Moderna, AstraZeneca, and Johnson and Johnson (J&J) – help the body to recognize and destroy the spike proteins in SARS-CoV-2 before it can trigger infection and cause disease.
Pfizer and Moderna vaccine makers use the messenger RNA (mRNA) approach. All they need is the genetic sequence of the COVID-19 virus – just the sequence – and not the virus itself. They use a little piece of the genetic material coding for a piece of the spike protein. Messenger RNA – a single strand of the genetic code that human cells can use to make a protein – instructs the muscle cells in the arm to make a particular piece of the virus’s spike protein called the “receptor binding domain” (RBD). When the vaccinated person encounters the wild COVID-19 virus the immune system recognizes it as foreign and is prepared to produce antibodies. That is, their immune system has be taught to “recognize” the virus and “remember” how to fight it off.
The mRNA is very fragile, so it is encased in lipid nanoparticles, which is a coating of a butter-like substance that melts at room temperature. That’s why Pfizer’s vaccine must be kept at ultra cold temperatures to transport and store. Moderna uses different formulations for the lipid nanoparticles and its vaccine can be transported more conveniently and can be kept stable for a month at home refrigerator temperature.
AstraZeneca and Johnson and Johnson are vector vaccines. The genetic recipe for the spike protein is carried into cells by a genetically engineered adenovirus, which has the COVID-19 virus spike gene encoded into it. Upon entering the host cells, the vector vaccines make the cells to produce the spike protein, to which the human immune system reacts, produces antibodies and activates T-cells to destroy the cells with the spike protein. Later, when the vaccinated persons catch the real COVID-19 virus, antibodies and T-cells are triggered and ready to fight the pathogenic virus to prevent infection and disease. Astra-Zeneca and J&J have less onerous cold chain requirements, and J&J requires only a single dose.
The four vaccines are effective to varying degrees at preventing serious COVID-19 illness, hospitalization and death. More recent data indicate they also prevent the onset of infection. Pfizer, Moderna and J&J can protect against disease due to variants.
A race between humanity and the virus
“The end is definitely in sight, but we’re not there yet,” said Prime Minister Trudeau in a recent briefing. “This third wave is more serious and we need to hang in there for another few weeks to make sure that we can flatten that curve, and drop those numbers down again to give a chance for vaccines to take hold.”
His is a call for collective Canadian engagement against the common pathogenic foe. Indeed, the original version of SARS-CoV-2 and its current and emerging variants are our common and formidable foes. The human toll has been enormous and shows no sign of retreat. To avert more COVID-19 tragedies we need collective understanding and focus from all our people, and cohesive, decisive leadership from our political leaders
There is no need to finger-point, to blame others, to find excuses, nor to dither on decisions. We must simply acknowledge that variants are our common formidable foes. It is not choosing to between protecting the seniors or the young, one group or the other, the rich or the poor, the most vulnerable or the least, nor between one province and another, nor one country and another nation.
May we reflect goodwill, share empathy, feel the pains of others, the fatigue and the stress of some.
We are all in this fight together. It is a race between humanity and SARS-CoV-2 and its variants.
Rey D. Pagtakhan, P.C., O.M., LL.D., Sc.D., M.Sc., M.D. is a retired lung specialist and professor, author and co-author of articles in medical journals and textbooks, former Parliamentary Secretary to the Prime Minister and cabinet minister, and member of the American Association for the Advancement of Science. In 2003, he spoke on the “Global Threat of Infectious Diseases” at the G-8 Science Ministers and Advisors Carnegie Group Meeting in Berlin, Germany.