The Covid-19 Vaccine: Herd Immunity - Part 2
As global vaccination rates rise and fall, hospitalizations fluctuate, and new variants arise, the end of the COVID-19 pandemic becomes less certain.
As of August 2021, approximately a third of the world has received at least one vaccine, and a quarter is fully vaccinated, leaving two thirds of the global population unvaccinated. In our previous post we discussed how global vaccination rates are tracking, the discrepancy between regions, and factors leading to vaccine hesitancy or other causes of not receiving it. Given these realities, how does this impact the end of the COVID-19 pandemic?
Herd Immunity - Can We Still Achieve It?
“Herd immunity” became a rallying cry around the COVID-19 vaccine. With herd immunity we could feasibly return to normal without fear of outbreaks. Diseases such as measles, mumps, chickenpox, and polio are all examples where herd immunity was achieved in the US through immunization. With COVID-19, the reality is that herd immunity may never be reached. To achieve herd immunity, there are two “paths” that can be followed: infections and vaccines. With COVID-19, there are pitfalls with both of these paths.
With infection, we run the risk of reinfection. The popular “chickenpox parties” of the 80s and 90s are not applicable for COVID-19 because, unlike chickenpox, an individual can become ill with COVID-19 more than once. Additionally, infection is a less desirable route for herd immunity because the COVID-19 virus has relatively frequent and potentially severe side effects that last much longer than the initial illness. One study showed that one third of those who had recovered were still experiencing side effects of the illness over 6 months later.
With vaccinations, there are large numbers of individuals not receiving the vaccine, whether due to hesitancy, uneven rollout, or lack of access, as discussed in the previous post. Some experts state that we would need to achieve 70-85% vaccination to “return to somewhat normal”.
If the current vaccination rate continues at its current pace, it would take 6 months to reach 75% global vaccination. However, this goal might not actually be enough. The Mayo Clinic put the vaccination coverage at 80-90% to near herd immunity. Greg Poland, director of the Vaccine Research Group at the Mayo Clinic, believes that even a rate of 95% would not achieve it, given the curveball of variants like Delta. Read more about how Delta is changing the way we understand COVID-19 in this post.
There is also a concern around waning vaccine efficacy. Over time, the vaccine’s ability to protect against COVID-19 decreases. This dip in efficacy creates more challenges for herd immunity as we will not remain immune to COVID-19 without booster shots or another method of illness prevention.
Without herd immunity, we could expect to see COVID-19 circulating for years to come. Looking at the 1918 Influenza Pandemic as the closest comparison in recent history, we can see waves of the virus debilitating countries and racking up large death tolls from 1918 through to 1920. This was not the end as most believe it to be, however; the 1918 flu has also cropped up in years since. In 1957, 1967, and 2009 we saw mutated variants of the 1918 “Spanish Flu” that proved to be more virulent and more deadly than the “seasonal flu”.
Without herd immunity, COVID-19 may have a similar fate. We could potentially see the virus continue to circulate in some form for decades. Even if the new forms of COVID-19 followed the same trajectory as influenza and became less impactful in some seasons than others, this would still seriously impact the world as we know it.
What all of this means is that globally individual organizations will likely need to include COVID-19 safety in their EHS processes for a lot longer than we had hoped. In our next post we will be discussing more about how workplaces are impacted and what we can learn from Israel’s recent experiences with COVID-19.
Want to know how other businesses have handled COVID-19 in their workplace?
Creating a Workplace Plan
Creating a COVID-19 Action Plan
Data in this article was obtained on 20/08/2021 and may not reflect current statistics for COVID-19 statistics or standards