Vaccine effectiveness

 Over at angrybearblog.com, Peter Dorman asks “what does vaccine effectiveness mean.”

This question is on the minds of those who are vaccinated and those contemplating vaccination, as well as physicians, vaccine developers, the CDC and government officials. Dorman writes: “ The everyday use of “effectiveness” is effectiveness against the virus. The research use is effectiveness relative to the control group. This is immense, but widely misunderstood and seldom explained.”
Yes, effectiveness in drug, device and vaccine trials is measured by comparing control/placebo group results to treatment group results. In the particular case of the COVID-19 vaccines, the trials are not challenge trials. It would be unethical to infect subjects with a potentially lethal virus like SARS-CoV-2. So the idea was that both groups would have some significant likelihood of natural infection that would be reportable in the trial (Disclosure: I’m in the Moderna Phase III trial).
Of course, we know that measured by the standards of their trials, the Moderna, Pfizer, J&J and AstraZenica vaccines all were “effective.” Since then, we have data from millions of vaccinated and unvaccinated people to back up that conclusion and it appears that the Pfizer vaccine will receive full FDA approval in September.
With the inevitable appearance of viral variants, the pressing question is how “effective” are the vaccines against each variant. The frontline assay has been to test antisera from vaccinated people for its ability to block virus from entering cells in culture. By that assay, all the vaccines have been deemed “effective,” albeit with somewhat lower effectiveness than for the original virus in some cases.
As Dorman acknowledges, one assay for vaccine “effectiveness” in the wild is whether it protects from infection. The problem with this is that most COVID-19 infections in both vaccinated and unvaccinated folks are inapparent, and those people are seldom tested, so we really don’t know what either the numerator or denominator are in those effectiveness calculations. More reliable are the statistics on hospitalization and deaths, and there, the performance of vaccines so far have been impressive.
Here’s an article from Nature that summarizes the current state of play. While the dominant theme is uncertainty, the data support the view that the vaccines are helping and that, until new vaccines are available, the best thing to fight new variants is for everyone to be vaccinated.
https://www.nature.com/articles/d41586-021-02054-z?WT.ec_id=NATURE-20210805&utm_source=nature_etoc&utm_medium=email&utm_campaign=20210805&sap-outbound-id=F8C7DC5800EB4926D8285EFA8E73396624E272C1

Comments

Post a Comment

Popular posts from this blog

Two sides

Image
  Yes, there are two sides to every question. In most cases, there is a correct side and a wrong side. In the case of Kamala Harris, the correct side is that she was born a US citizen. The wrong side is that her parents had to be citizens or permanent residents for her to be a citizen. President Trump pretended to be unsure about this, just as he pretended for five years that Barack Obama is not a citizen. In the case of the Harris noncitizen claim, it is backed by the racist C laremont Institute: "The Claremont Institute masquerades as an intellectual salon of the right, but it is really just a racist fever swamp with deep connections to the conspiratorial alt-right. It even granted a fellowship to Jack Posobiec, who helped promote the notorious Pizzagate conspiracy theory. Claremont’s resident bigots offer deranged fantasies of violently expelling Americans from their home country because of their ethnic backgrounds. Their work deserves the intellectual weight given to that of D...
Read more

Who chooses?

Over at jabberwocking.com , Kevin Drum blames pro-choice writers for failing to make the case for reproductive choice. Well, from everything I've read, a clear majority of Americans believe that Roe should still stand. Seems like the case has been made, and if we lived in a truly representative democracy, a limited national right to abortion would be preserved. But beyond that reality, I think Drum has it exactly backwards. Why does the burden of proof fall on those advocating for personal autonomy? Seems to me the null hypothesis is that women should be allowed to make decisions about their own health, and that the justification for nanny state intrusion into such decisions rests with the minority who assert state coercion. Democrats need to hammer on the right-wing GOP to explain why the government takes temporary custody of pregnant Americans. https://jabberwocking.com/liberals-really-suck-at-defending-abortion/
Read more

Black Earth

 Just finished reading “Black Earth: The Holocaust as history and warning” by Timothy Snyder. It is a detailed account of the Holocaust, as well as an effort to abstract lessons from this history for our time. Like his book “Bloodlands,” Snyder’s “Black Earth” makes for painful reading. As the grandson of a Ukrainian Jew and the son of a Jew, I would have been targeted in the Holocaust had I been in the wrong place. I had read several histories of Europe in World War II that included the Holocaust. I knew the basic story of the Holocaust and Hitler’s anti-Semitic vision. I learned a great deal by reading this book. I won’t belabor the ghoulish atrocities committed by the Nazis and their collaborators. To summarize them here would be to trivialize the enormity of the crimes and invite pointless debate about who did what and who suffered more. You’ll have to read the book to understand Snyder’s historical insights. However, I learned many things that I did not know by reading thi...
Read more