Thread by @VikiLovesFACS

Most of the very extensive data showing that #CovidVaccines are safe and effective in #pregnancy was collected in the general rollout.

Is this okay? Shouldn’t we have trial data?

Let’s talk about the ethics of vaccine trials in pregnancy! 🧵…

drive.google.com/file/d/1_wHIYX…

First, let’s note that we do have some data on pregnancy from the COVID vaccine trials. Participants were asked not to become pregnant, but some did by accident. The outcomes for these pregnancies were monitored as part of the trials, with no concerns emerging. 2/

https://twitter.com/VikiLovesFACS/status/1560272931720011779

Because…

1. What little data we had was reassuring

2. What we know of 💉 biology suggested there would not be any problems in 🤰🏻

3. COVID 🦠 *does* cause problems in pregnancy

… some countries 🇺🇸 🇮🇱 opted to offer the 💉 and let 🤰🏻 decide

3/

Lots of my colleagues who are obstetricians and paediatricians, and had seen the harm COVID 🦠 can cause in pregnancy were first in line! 4/

https://twitter.com/vikilovesfacs/status/1425843845405761538

These ppl were told about what (little) data was available on these vaccines as well as the data on the harms of COVID 🦠 in pregnancy, and made an informed choice.

We collected data from the 1st 🤰🏻 vaccinees so future ones (in other countries) would be better informed.

5/

So was rolling the vaccine out to 🤰🏻 without trial data in that population okay?

They made an informed choice and safety was closely monitored, so I would say… yes.

But could we have done better?

Also yes! 6/

How? By including 🤰🏻 in the first round of clinical trials. This has 2 benefits…

1. Justice. It’s not fair ppl be excluded from the potential benefits of being in a trial just because they’re 🤰🏻

2. Knowledge. 🤰🏻 being offered 💉 in the general rollout wd have better info. 7/

Guidelines for the ethical inclusion of 🤰🏻 in vaccine trials were developed for use in Ebola and Zika outbreaks.

These could - and should - have been used in the COVID pandemic. We must do better next time. 8/

ncbi.nlm.nih.gov/pmc/articles/p…

But can’t we exclude 🤰🏻 from the first round of trials, and only include them once we know a 💉 is safe and effective in the general population?

This is actually what we tried: Pfizer started a trial in 🤰🏻in February 2021.

But there are two problems with this approach… 9/

1. In a public health emergency, we need the data urgently. During the delay between the first trial data and that from 🤰🏻, this population will be in the same position as before - making a decision on limited data. 10/

2. If - as happened - it emerges from the general rollout that it’s much safer to get vaccinated than to remain unvaccinated, the placebo group in your trial will want to get vaccinated. And it’s not ethical to prevent them. 11/

This means you will only have a very short window of time where your trial is placebo controlled and blinded, which limits the ability to follow up outcomes in the control group and thus the usefulness of the trial. 12/

Because of this, lots of people (and me!) would advocate including pregnant people in the first round of vaccine trials in public health emergencies.

I’m going to link the guidelines developed for doing this again, because they’re great! 13/

ncbi.nlm.nih.gov/pmc/articles/p…

Finally, why have I written this thread? In short because a lot of people have been asking “Is it okay that our safety in pregnancy data comes from the general rollout?” so I thought it was worth taking the time to write a nuanced answer to them. 14/14