The Bias that Creates the Illusion of an Effective Covid Vaccine

The Bias that Creates the Illusion of an Effective Covid Vaccine. By Dr. Eyal Shahar, a professor emeritus of public health in epidemiology and biostatistics.

The prevailing narrative tells us that vaccinating the frail and elderly against Covid had a dramatic effect on mortality.  …

But vaccine effectiveness in the elderly simply cannot be as high as touted:

Studies of vaccine effectiveness (thereafter, VE) reported a remarkable result that should have surprised knowledgeable readers. Estimates for the elderly have been extremely high, sometimes similar to those for younger age groups. For instance, a study in Israel of elderly residents of long-term care facilities reported VE of 85 percent against Covid death.

That is not only contrary to basic knowledge from immunology but is also incompatible with the following observation:

After the second vaccination [by the Pfizer vaccine] 31.3% of the elderly [over the age of 80] had no detectable neutralizing antibodies in contrast to the younger group, in which only 2.2% had no detectable neutralizing antibodies.

Consider three facts:

  1. Almost one-third of the elderly (over the age of 80) do not develop antibodies after vaccination against Covid
  2. Vaccine-induced immune response is known to attenuate with aging
  3. Flu vaccines do not offer high protection in the elderly

How could Covid vaccines have been highly effective in the frail and elderly?

They were not.

The major bias: Unhealthy people don’t get vaccinated as much.

A naïve comparison of vaccinated people with unvaccinated people is grossly misleading because of the “healthy vaccinee” bias, demonstrated repeatedly and better explained in the reverse direction. People who are not vaccinated are, on average, less healthy than their vaccinated counterparts, and therefore have higher mortality in general. The mechanisms behind this phenomenon deserve a separate discussion, but it is well documented, nonetheless. Previous research on flu vaccines has also shown that the bias is not easily removed by conventional statistical methods.

We have … studies that compared non-Covid mortality in the two groups. Since Covid vaccines are not expected to reduce non-Covid mortality, any ratio higher than 1 is an estimate of the bias factor. Based on data from the US and the UK, … the mortality rate of unvaccinated is 2 to 3 times the mortality rate of vaccinated.

Those who were vaccinated against Covid were less likely to die — from non-Covid causes! — than their unvaccinated counterparts.

Once the bias factor is estimated, say 2, correction of biased VE is simple.

Consider, for example, that biased VE of about 50 percent from Sweden, which was based on a comparison of vaccinated and unvaccinated residents of nursing homes. VE of 50 percent is derived from a (biased) risk ratio of 0.5: vaccinated appear to be at half the risk of Covid death, or vice versa: unvaccinated appear to have twice the risk of Covid death (supposedly because they were not vaccinated).

Since the latter have twice the risk of death to begin with, vaccination has made no difference.

If the bias factor was only 1.5, that biased VE of 50 percent from Sweden will be corrected to 25 percent, much closer to futile than to a highly effective vaccine.

Conclusion: The effectiveness of covid vaccines in the elderly is low, perhaps zero. It only appeared good because of the “healthy vaccinee” bias. Oh dear.