If You Do not Advocate AstraZeneca Vaccine For The Aged You Are Risking The Lives Of The Most At Danger – Watts Up With That?
Jonathan Pugh, University of Oxford and Julian Savulescu, University of Oxford
Regulators in Europe are divided on whether the Oxford / AstraZeneca vaccine should be given to the elderly. In the UK, the vaccine was approved for use in adults aged 18 and over. However, France, Germany, Sweden, and Austria say the vaccine should be prioritized for those under 65. Poland only recommends it for people under 60 years of age. Italy goes one step further and only recommends it for people under 55 years of age.
It is only ethical to approve a vaccine if it is safe and effective. Crucially, the reluctance to approve the AstraZeneca vaccine in the elderly is based only on concerns about its effectiveness.
The concern is not that there is data to show the vaccine is ineffective in the elderly, but that there isn’t enough evidence to show it is effective in this age group. The challenge is how to deal with the level of uncertainty about the effectiveness of the vaccine given the evidence available.
How much data is there? The AstraZeneca Vaccine Study Interim Results summarized data from over 11,000 participants who received two doses of the AstraZeneca vaccine or a placebo. Another report shows that only 660 participants were over 65 and there were only two cases of COVID in this group. Due to the small number, the study’s authors conclude that the effectiveness of the vaccine in the elderly could not be determined. By comparison, the published Pfizer vaccine study included nearly 38,000 participants; Around 16,000 of them were over 55 years old.
There is also data on the extent to which the AstraZeneca vaccine elicits an immune response. One study analyzed whether the vaccine elicited an immune response in 560 participants, including 400 participants over 55. Previous human studies found that after the second dose, the vaccine produced similar immune responses in all age groups. While this is not evidence that the vaccine prevents symptomatic disease, it does suggest that the vaccine has an important effect in the elderly.
An ethical rather than a scientific disagreement
The disagreement over whether the vaccine should be recommended for the elderly is more an ethical than a scientific question: what standard of evidence do we need to determine the effectiveness of a vaccine before approving it for use in a pandemic?
The more evidence there is, the greater the certainty that regulators can have the effectiveness of a vaccine and which distribution strategies will maximize the public health benefits. However, gathering evidence takes time. The higher the standard, the greater the delay before people can access the intervention. This compromise is particularly acute in the case of the pandemic. Time here is life.
Consider the following rough calculations based on publicly available statistics. There were 14,633 COVID deaths in the UK from November 28, 2020 to January 1, 2021, according to the Office of National Statistics. Only 1,351 of these deaths were in the 20-64 age group; 13,280 were in people over 65.
Imagine if the UK was able to fully vaccinate everyone between the ages of 20 and 64 with a 95% effective vaccine before November 28, 2020. For example, suppose preventing coronavirus infection was enough to avoid all of the above deaths. Assuming this, the vaccine could have been expected to prevent 1,283 deaths between the ages of 20 and 64 years.
Now let’s say we could have vaccinated anyone over 65 with this vaccine, but there was limited data on how effective it would be in the elderly. Here’s the crux of the matter: to save the same number of lives (1,283) in those over 65, the vaccine would only need to be just under 10% effective given the far higher mortality rate among older people.
This generously assumes that the vaccine is very effective under 65. If the vaccine were 70% effective in the 20 to 64 year old age group, it would only have to be 7.1% effective in the elderly to be expected to save the equivalent number of lives (946 in this case).
Here is another example. A recent study suggests that the average risk of death for 60 to 64 year olds infected with coronavirus is 0.46%. For a person aged 80 and over, the risk is 8.3%. Again, generously assume that a vaccine is 95% effective in 60 to 64 year olds. This means that for every 1,000 people vaccinated in this group who would have been infected, the vaccine would save 4.3 lives. How effective would a vaccine have to be in people 80 and over to still save the same number of lives? 5.2%.
We are not suggesting that the effectiveness of the AstraZeneca vaccine in the elderly is so poor, or that regulators should approve a vaccine that is as ineffective as this imaginary one. The World Health Organization has set a minimum effectiveness of 50% for COVID-19 vaccines. However, these examples show the importance of considering the limitations of efficacy (or its evidence) with the real risk of mortality to which people without a vaccine are exposed.
A vaccine of limited effectiveness is problematic if it prevents access to other effective interventions available. However, other vaccine stocks are currently scarce and their assessment in the elderly is also ongoing. In the meantime, people over the age of 65 are at an exponentially increasing risk of death. Without other effective prophylactic measures, a vaccine can be far less effective in older groups and still save many lives.
Jonathan Pugh, research fellow at Oxford University and Julian Savulescu, visiting professor of biomedical ethics at Murdoch Children’s Research Institute; Distinguished Visiting Professor in Law, University of Melbourne; Uehiro Chair in Practical Ethics, Oxford University
This article is republished by The Conversation under a Creative Commons license. Read the original article.
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