Wondering if antibodies raised against #COVID19 #vaccines can bind to the placental protein syncytin-1 and harm #fertility?


Out yesterday! More data that addresses this question!

Spoiler alert: they don’t... 🧡

But why would anyone even think that such a thing might happen? Is it even worth researching?

The rumours that COVID19 vaccines would impact fertility were started by a vaccine skeptic who proposed that this might occur, so this is something that a lot of ppl may have heard. 2/
People who work in this area never thought this was very likely, for a number of reasons.

Not least, if this did happen COVID 🦠 would be associated with infertility or problems in early pregnancy, and luckily we don’t see that. 3/

And this preprint came out in May, showing that antibodies raised by vaccination don't bind syncytin-1. 4/

This new study has been peer-reviewed and uses a slightly cleaner assay, which makes the results clearer.

πŸ‘‰πŸ» Antibodies from vaccinated people bind to COVID19 spike protein (as expected), but not to syncytin-1. 5/
They also took a look at antibodies from people who had been infected with COVID19 🦠. They also bind to COVID19 spike protein, but not to syncytin-1. 6/
So can we please put to bed this idea that #COVID19 #vaccines can raise an immune response to syncytin-1, harming #fertility?


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More from @VikiLovesFACS

12 Oct
A question I get asked *a lot* is…

β€œWhat are the long-term effects on babies born after #COVID19 #vaccination in #pregnancy?”

So let’s talk about what we know… 🧡
Let’s start by looking at the effects at birth. We now have eight large datasets from four countries looking at almost 79,000 people vaccinated in pregnancy. The outcomes for the babies are all normal. 2/
(The CDC has recently put out data from 2 more US studies, bringing the total to 10. But there is some overlap between the participants in these studies and the ones quoted above, so I didn't add those in as unique participants.)

From V-safe... 3/

Read 12 tweets
8 Sep
This study looked at the effectiveness of the Pfizer #COVID19 #vaccine in #pregnancy.

πŸ‘‰πŸ» 96% effective vs. any infection

πŸ‘‰πŸ» 97% effective vs. symptomatic infection

πŸ‘‰πŸ» 89% effective vs. hospitalisation


A few additional points…

Why is effectiveness vs hospitalisation lower than against all infection? This is the opposite of what we see in larger studies of the whole population, eg. this PHE data… 2/

Very few people were hospitalised (5/10,861 in the unvaccinated group compared to 0/10,861 in the vaccinated group).

This means the confidence interval for effectiveness vs hospitalisation was wide (43 - 100%) which is likely to have lowered the central estimate. 3/
Read 6 tweets
17 Aug
On holiday without much in the way of internet, but wow! My notifications blew up when I hit some WiFi this afternoon. A few points on this… 1/
First, I’m surprised neither of them checked our national guidance, which is set out in detail for medical professionals here… 2/

Or the guidance from @RCObsGyn and @MidwivesRCM, which makes a clear recommendation that #pregnant people get the #COVID19 #vaccine. You can find it here… 3/

Read 7 tweets
13 Aug
New data from the V-safe pregnancy registry on the safety of #COVID19 #vaccines in #pregnancy!

πŸ‘‰πŸ» 2456 people vaccinated before 20 weeks of pregnancy

πŸ‘‰πŸ» Followed up to 20 weeks

πŸ‘‰πŸ» No increased risk of miscarriage following vaccination.


This is a follow-up to this older study in the same cohort. The older version of the study showed no increased risk of miscarriage following vaccination, but the follow-up time was shorter (10-12 weeks). 2/

Although the data from this study was reassuring, the limited follow-up time made it difficult to exactly calculate the miscarriage rate following vaccination, so an estimate was used.

I’ve discussed that here… 3/
Read 11 tweets
10 Aug
Who's been waiting for UK data on the safety of #COVID19 #vaccines in #pregnancy? πŸ’‰πŸ€°πŸ½πŸ‡¬πŸ‡§πŸ€”


Well now we have some!

(TLDR: No concerns arising from this study)... 🧡

This study looked at people coming to give birth at St George's hospital in London between March 1st and July 4th 2021.

141 had had at least one dose of a COVID vaccine

1187 were unvaccinated. 2/
(And for those always on the hunt for data about the AstraZeneca vaccine in pregnancy... 13 of the vaccinated people had had AZ.) 3/
Read 7 tweets
19 Jul
After I wrote this thread about the potential effects of COVID vaccination in pregnancy and the lack of such effects in other vaccines, perinatal epidemilogist @deshaynef got in touch to tell me about some work she has done in this area... 🧡
Her group has published two papers doing 3-5 year follow-up on the babies of people vaccinated against flu in pregnancy.

πŸ‘‰ Flu vaccination in pregnancy was not associated with adverse outcomes in children later on. 2/
Read 5 tweets

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