With shipments of vaccines just around the corner, it is time to speculate upon the implications of their implementation. Given that there are already two companies – Pfizer and Moderna –promoting vaccines with 95% efficacy, and a third, AstraZeneca, offering another that is easier to transport and store, we may be tempted to conclude that these products will stop COVID-19 in its tracks and allow us to return to our pre-pandemic lifestyle. Thus, it is hardly surprising that governments are zealously and hastily jump-starting research and development while competing with one another to ensure the quickest possible availability of millions of vaccine doses for their citizens.
Should we expect imminent eradication of the virus and a return to pre-pandemic social behavior? While previous experience with other vaccines suggests that an effective vaccine should significantly slow down the spread of COVID-19 and reduce illness and mortality, I believe that desperation or misunderstanding has fostered unrealistically high expectations which will be thwarted: the vaccines are unlikely to provide a panacea, much less an instant remedy.
To understand why we should put a damper on our initial unbridled enthusiasm, we need to look at the ins and outs of effective vaccine use. The 95% efficacy rate shown by initial research refers to the vaccine’s performance under ideal circumstances. 95% sounds high, even very high. However, what really counts is the vaccine’s effectiveness in practice (in contrast to ideally) on large populations. Effectiveness is always lower than efficacy, for a variety of reasons. Here are some of them:
Adoption: Not everyone will agree to be vaccinated. Obviously, the vaccine can work only on those who receive it. A global survey done in June found that only 71.5% of participants would be very or somewhat likely to be inoculated, and in an American survey in September a dismally low 49% of those questioned reported that they would definitely or probably not get vaccinated. We should note that the survey results indicating a low level of willingness to be inoculated do not even relate to specific anxieties about any of the COVID-19 vaccines, as no significant problems have been reported to date. If troubles crop up along the way, the percentage of people who agree to be vaccinated will probably drop even further.
Although it is encouraging to know that an effective vaccine can make 100% difference for an individual, virus spread cannot be controlled until a high enough percentage of the population is rendered immune to infection. A 2006 study suggested that inoculation of least 60% of the population is necessary in order to provide an effective country wide intervention.
Logistical issues: We have seen the world over how long it took (usually many months) before most countries were able to successfully set up an effective COVID-19 testing system on a national scale. The logistical obstacles involved in nationwide inoculation are far more challenging, especially since vaccine stability requires special cold transportation and storage conditions. The Pfizer vaccine must be kept at -70 degrees, and most countries lack the necessary refrigeration facilities. While I am confident that, in time, such problems can be overcome – and, indeed, Pfizer is already working on a solution – successful resolution may not be smooth and will probably not be immediate.
Availability and mass inoculation: As countries vie with one another to receive millions of doses, a short-term vaccine shortage could occur. However, this may not be the main problem because, even if vaccines are readily available, many countries will lack the capacity to inoculate everyone quickly. The inability to inoculate large population sectors quickly and all inclusively is liable to prove a greater rate-limiting factor than vaccine availability.
Delay: Because of logistical challenges and possible availability issues, considerable time will probably elapse between the day the vaccines land at the airport and the attainment of a massive inoculation campaign.
In short, the jury is still out as to when mass inoculation will be accomplished and how effective on a national level vaccine program application will be. I believe we are looking at a period of many months.
There are still nagging and potentially problematic questions whose answers will become evident only long after inoculation has begun.
- The decision of governments to go forward and authorize vaccine usage short-cutting the approval process should raise some eyebrows; for example a notice in the FDA website dated Nov 27 states “ Currently, there is no FDA-approved or authorized vaccine for the prevention of COVID-19.” Traditionally countries and not just the U.S. wait for FDA approval before authorizing use of new medical technologies.
- Does the vaccine have any rare but serious side effects? Such problems are often encountered and identified only after the vaccination of much higher numbers of people than participated in early studies.
- A related question that we cannot answer yet is: Does vaccination have any long-term effects?
- Duration of immunity: How long is the period of immunity conferred by the vaccine? Months? Years?
- Does vaccination preclude being a carrier: Can a person who has received the vaccine still be a carrier and spread the virus?
- Laboratory precision on vaccine protection: Is there an accurate correlation between antibody levels from the vaccine and actual protection from the virus? If not, those inoculated will not know for certain whether or not they are protected.
- The possibility of mutation: The flu vaccine requires reformulation each year because the flu virus undergoes changes: it mutates in such a way as to render the vaccine that is effective this year liable to be ineffective next year. COVID-19 seems to mutate much less, but there is already one refined mutated strain of the virus that can expedite cell penetration. One cannot rule out the possibility of a mutation rendering current vaccines partially or totally ineffective.
- The potential for error: The combination of hasty massive vaccine development using innovative methods together with an accelerated approval process – to allow soonest possible vaccine use – is a setup for inadvertent errors. The Cutter incident of 1955, in which 120,000 defective polio vaccine doses actually carried the virus and infected over 40,000 people with the disease, is a historic example. AstraZeneca recently acknowledged an error in their research program, nullifying 3 months’ research which will now have to be repeated. While we can assume that the pharmacological companies will do everything in their power to prevent error, unexpected mistakes can nonetheless occur, especially when rushed and using a novel technique on a mass scale.
- And, most relevant: Will those of us who have been inoculated, and the elderly ill in particular, still need to practice social distancing?
Looking ahead and peering into the future – a sure exercise in fallibility – I believe that, barring unpleasant surprises, we can nonetheless draw some tentative conclusions.
- If a high enough percentage of the population is inoculated, the spread of the disease, severe illness and mortality should be significantly reduced. While it is still too early to speculate on the timing and even possibility of complete virus eradication, past evidence with historical pandemics do foretell an eventual optimistic outcome.
- People who have been inoculated will be much safer. Even if they do not become totally immune (only time will tell), for 95% of those who receive the vaccine under proper conditions the risk of contracting COVID-19 should be at the least, very low.
- Initially, until we see a definite epidemiological turnaround, physicians and governments will, for the most part, continue to insist that we maintain precautionary social and hygienic behavior, especially where the vulnerable including the elderly ill are concerned.
Their own vested interest aside, the pharmaceutical companies are doing their share to help the world deal with COVID-19. Governments, confronted by the stark imperative of a dangerous pandemic that shows no signs of abating and which continues to affect millions of people, find themselves helpless in an unfamiliar predicament with the present social and economic price for virus control too prohibitive. Consequently, the logical course is for them to promote widespread use of potentially effective vaccines as soon as possible. It would, however, be unrealistically misleading to assume that because of vaccine availability the path to virus eradication will be glitch free. It is more likely that we will encounter missteps, miscalculations, and perhaps more serious complications along the way. In the meantime, it behooves us to remain realistic and levelheaded in our anticipation of how swift and smooth the turnaround may be.