I do not want to get into an argument about whether you should or should not get COVID vaccinations. Or how to overcome vaccine hesitancy in the public. Much as Vinay Prasad does, I read research studies to evaluate the conclusions drawn from the results of data.
I have recently read an article from the American College of Obstetrician sand Gynecologists (ACOG) journal about data collected from the Centers for Disease Control and Prevention (CDC) Vaccine Safety Datalink to analyze whether or not the COVID vaccinations given during pregnancy caused stillbirths. The intent of the study was to demonstrate that giving vaccines during pregnancy did not cause stillbirths, and therefore should be a study to help overcome vaccine hesitancy.
Parden the going down the rabbit hole to identify where this data is coming from, but where data comes from often plays a large part in bias in research studies. The CDC Vaccine Safety Datalink collects vaccination data from 13 large healthcare systems in nine states. This narrow field of data collection means the data does not represent vaccine results in the majority of the states. To me, this is a red flag.
In reading the article, I found the authors called the study robust in several different places. Whenever I see that word, “robust” used so many times I find myself wondering exactly why it's necessary to pitch the point with so much vigor.
With any research study, I look for some indication of the efficacy of the approach being studied, the evidence that the conclusion of the study works. The article concludes that there is no risk of increased stillbirths in the second half (20 to 40 weeks of pregnancy) with the addition of the vaccine. This is not efficacy, but an estimate of risk.
If I were a pregnant woman and my doctor suggested I get the Covid vaccination, my first question would be "Why should I get this shot?" In other words? How will this vaccination benefit me and my baby? Efficacy is the same as benefit. This study has not indicated the benefit of Covid vaccinations. Benefit should be the main concern about getting vaccinated. Simply demonstrating that there is no harm is neither convincing, nor sufficient. Efficacy equals benefit.
What’s missing in this study and the article's conclusion is a demonstration of efficacy. Simply telling the public that there is no increased risk doesn’t automatically persuade patients to become vaccinated unless there is also some associated benefit. In other words, why get vaccinated if it doesn’t make any difference?
I find the premise and the argument in this study weak and not at all compelling. So, why would the average pregnant woman want to take a Covid vaccination if it is not associated with documented, provable benefit?
Another problem with the study is that we really don’t know what the control group is. In other words, there was the group with miscarriage or stillbirth, and the group without stillbirth.
There is a control group which was not vaccinated during pregnancy. But what we don’t know is whether they may have been vaccinated once or twice before pregnancy. So, in other words, we really don’t know whether those in the control group were vaccinated before their pregnancy rather than just not during their pregnancy.
Ideally, the control group should not be vaccinated—ever. If the control group has been vaccinated at some other time we don’t really know whether the Covid vaccine provided during pregnancy really is safe. I have not seen documented anywhere in this study the vaccination status of subjects prior to pregnancy.
Finally, the study endpoint of stillbirth is not a good canary in the coal mine. Much morbidity (illness) may occur in dozens of gradations which cause illness but not death, at least not right away. We are left with the absence of evidence regarding any illnesses which may be associated with getting the shot during pregnancy.
There have been cases of babies born with myocarditis associated with vaccine use in fetuses, babies, and in young people. Since the authors did not include assessment of morbidity, it’s difficult to quell vaccine hesitancy with this study. “Robust” is not the word I would use to describe this study. By the way, this is a CDC-supported study, so the “robust” part might be mainly because the authors are trying to impress the CDC.
It is very difficult to read research studies and evaluate them if you are not trained in medicine and research statistics. Many journals block the public's access to research articles although the journals provide reporters with copies, or at least PR hype about the studies. My advice? Be very wary of the conclusions you may read about in the press regarding research studies. The competition amongst medical researchers to publish papers is profound. My problem is that medical journals such as that of ACOG should be more careful in what they approve for publication. ACOG's publication of this article appears to be a sign of the organization's bias—COVID shots are good for pregnant women. ACOG's editors should be able to see the flaws in this study and pass it by.