Immunologist working on pregnancy at @ImperialCollege | equality and diversity in STEM | she/her | Because VikiLovesNKCells was too long for Twitter
3 added to My Authors
May 5 • 10 tweets • 7 min read
@BerryTartlet@DrLoupis Yes, this is quite an old document. A timeline of UK policy on this might help you.
8 - 31 Dec 2020. Vaccines approved, but using the same exclusions as the trials - no-one who is or could be pregnant. That’s the document you’re looking at there. 1/@BerryTartlet@DrLoupis Also worth noting that even at that point, there’s nothing saying it’s not safe, only pointing out that we don’t have any evidence yet. 2/
Jan 29 • 11 tweets • 7 min read
@jtmayes3@kevinault Let’s begin by taking the 172,000 number at face value. About 190,000 ppl have been vaccinated during pregnancy in the US. So if that were true it’s a miscarriage rate of 90%…
1/
cdc.gov/coronavirus/20…@jtmayes3@kevinault Quite apart from being not plausible, it’s straight up impossible. Miscarriages by definition happen before 20 weeks and about half of those vaccinated were vaccinated after 20 weeks. It was too late for them to have a miscarriage. 2/
nature.com/articles/s4159…
This gives us some homegrown data on vaccine effectiveness in pregnancy, including in the delta wave. Roughly speaking, vaccination reduces the risk of...
I know ppl have been wondering about this! But up to now the data we had was pretty preliminary. However, with a large, prospectively collected dataset out yesterday, I think it’s time to start putting it all together.... 🧵
Here’s some more on that new study. In short, people who received both doses of the vaccine in a single menstrual cycle found their period came a couple of days late. But it was back to normal a couple of cycles later, so the change was temporary. 2/
In summary: on average, periods are delayed by ~half day by dose 2 of the vaccine, and delayed by ~2 days if you get both doses in the same cycle. But it's temporary! 🧵
2403 were vaccinated. Taking them all together, the average period came 0.64d late after dose 1 and 0.79d late after dose 2. No difference in length of period. 2/
In people giving birth between January and August, 24,759 of whom were vaccinated...
🗝️ No difference in stillbirth rate between vaccinated and unvaccinated... 1/
🗝️ No difference in babies with low birthweight between vaccinated and unvaccinated... 2/
@RCObsGyn encourage all pregnant ppl in the UK to get their booster when they are offered it... 1/
rcog.org.uk/en/guidelines-…
If you are in the USA and pregnant or recently pregnant, you will be offered a booster vaccine as soon as you are six months out from dose 2. And @acog recommends you get it. 2/
Cohort 1 consists of 250 people recruited before they received their COVID vaccine, who are keeping a record of their periods before and after vaccination. 2/
Nov 3, 2021 • 10 tweets • 4 min read
A bunch of people have been in touch about this paper. Has a review of the evidence really raised questions about the safety of the Pfizer #COVID19#vaccine in #pregnancy?
The paper purports to present a reanalysis of the V-safe pregnancy registry data to the end of February. You can find the original report (which concluded no increased risk of pregnancy complications following vaccination) here… 2/
Stressful times (war, famine) are associated with people experiencing more anovulatory and abnormal menstrual cycles.
But what about the pandemic? This paper used data from 18,076 ppl tracking their cycles with @NaturalCycles app to investigate… 🧵
journals.plos.org/plosone/articl…
The authors looked at user data entered from March - September 2019 (pre-pandemic) compared to March - September 2020 (Pandemic). They also asked users to rate their stress levels (retrospectively) in the pre-pandemic and pandemic periods. 2/
🧵...
People who are breastfeeding can sometimes get forgotten in the focus on pregnancy. But your questions matter too! And I particularly want to make space to address those questions because a lot of people have contacted me, worried about one particular blog post... 2/
Oct 14, 2021 • 7 tweets • 4 min read
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... 🧵
nature.com/articles/s4142…
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/
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/
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/
👉🏻 2456 people vaccinated before 20 weeks of pregnancy
👉🏻 Followed up to 20 weeks
👉🏻 No increased risk of miscarriage following vaccination.
🧵…
researchsquare.com/article/rs-798…
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/