I was operating under the impression that the COVID-19 vaccine would work something like this:
- A vaccine is rolled to at-risk groups and then to the general population
- A sufficient portion of people that get the vaccine produce an immune response similar to that which occurs during a natural infection and gain immunity from the disease, at least for a time
- In addition to no longer being susceptible to the disease, they also no longer serve as carriers of the disease and don’t pass it to others
- The combination of natural herd immunity and vaccine-induced immunity removes enough vectors of transmission that the disease stop spreading outside of pockets where immunity is lacking for some reason
I’m under the impression that most of the public is using this mental model when they’re thinking about a vaccine for COVID-19. As in, once a person takes the vaccine, they’re more or less “safe,” and once through this process we’ll be able to return to normal life.
I recently came across a couple articles that caught me by surprise. First, this article from The Lancet (bolding mine):
A first generation of COVID-19 vaccines is expected to gain approval as soon as the end of 2020 or early 2021. A popular assumption is that these vaccines will provide population immunity that can reduce transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and lead to a resumption of pre-COVID-19 “normalcy”.
Multiple COVID-19 vaccines are currently in phase 3 trials with efficacy assessed as prevention of virologically confirmed disease. WHO recommends that successful vaccines should show disease risk reduction of at least 50%, with 95% CI that true vaccine efficacy exceeds 30%. However, the impact of these COVID-19 vaccines on infection and thus transmission is not being assessed. Even if vaccines were able to confer protection from disease, they might not reduce transmission similarly.
These observations suggest that we cannot assume COVID-19 vaccines, even if shown to be effective in reducing severity of disease, will reduce virus transmission to a comparable degree. The notion that COVID-19-vaccine-induced population immunity will allow a return to pre-COVID-19 “normalcy” might be based on illusory assumptions.
Also, this article by William A. Haseltine, former professor at Harvard Medical School and founder of Harvard’s Division of Human Retrovirology:
Moderna, Pfizer, AstraZeneca, and Johnson & Johnson are leading candidates for the completion of a Covid-19 vaccine likely to be released in the coming months. These companies have published their vaccine trial protocols. This unusually transparent action during a major drug trial deserves praise, close inspection of the protocols raises surprising concerns. These trials seem designed to prove their vaccines work, even if the measured effects are minimal.
Prevention of infection must be a critical endpoint. Any vaccine trial should include regular antigen testing every three days to test contagiousness to pick up early signs of infection and PCR testing once a week to confirm infection by SARS-CoV-2 test the ability of the vaccines to stave off infection. Prevention of infection is not a criterion for success for any of these vaccines. In fact, their endpoints all require confirmed infections and all those they will include in the analysis for success, the only difference being the severity of symptoms between the vaccinated and unvaccinated. Measuring differences amongst only those infected by SARS-CoV-2 underscores the implicit conclusion that the vaccines are not expected to prevent infection, only modify symptoms of those infected.
We all expect an effective vaccine to prevent serious illness if infected. Three of the vaccine protocols—Moderna, Pfizer, and AstraZeneca—do not require that their vaccine prevent serious disease only that they prevent moderate symptoms which may be as mild as cough, or headache.
One of the more immediate questions a trial needs to answer is whether a vaccine prevents infection. If someone takes this vaccine, are they far less likely to become infected with the virus? These trials all clearly focus on eliminating symptoms of Covid-19, and not infections themselves. Asymptomatic infection is listed as a secondary objective in these trials when they should be of critical importance.
He goes on to critique the very low bar of “success” for these vaccine trials and points out that the only thing they’re evaluating, essentially is the presence or absence of mild cold symptoms between the experimental and control groups.
The average person thinks a vaccine will protect them from infection, not cause a mild reduction in severity of “moderate” symptoms. I believe when most people say “we need to wait for a vaccine,” this is not what they have in mind. Am I wrong in thinking this?
Also, if a reduction in infections isn’t likely to occur even with a vaccine, doesn’t this imply focusing on number of cases when making policy decisions will lead to endless restrictions? Maybe I’m interpreting this too pessimistically, but it seems like the light at the end of the tunnel is farther away than I thought.