There’s a big data gap when it comes to vaccines and pregnancy

Getty Images / WIRED

More than 137,000 people in the UK have had their first doses of the Covid-19 vaccine – the start of a long mass vaccination process that will continue well into next year. But there is one group of people who are being advised to avoid taking the vaccine even if they fall within one of the government’s nine priority groups for early vaccination: pregnant and breastfeeding women.
The government’s official advice states that pregnant women should not receive a Covid-19 vaccine and neither should those who are breastfeeding. In the US and Canada, however, regulators are allowing some pregnant people to make the decision as to whether they have a vaccine or not. So why is there a difference?


In the UK, pregnant people are classed as being at moderate risk from Covid-19 – the same category as those over 70, or with conditions such as diabetes. In November a study from the Centres for Disease Control and Prevention (CDC) in the US found that pregnant women were at increased risk of severe Covid-19 compared to non-pregnant women of the same age. But we have very little data about the safety of the BioNTech/Pfizer vaccine in any person who is pregnant or breastfeeding, as they were excluded from trials, as is normally the case.
Because of the dearth of data, the UK’s medical regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), has said those who are pregnant or breastfeeding will not be getting a jab. “The clinical trials for the Pfizer/BioNTech Covid-19 vaccine did not include pregnant or breastfeeding women,” the MHRA said in a statement.
“Therefore, as a precautionary measure our recommendation is that the vaccine should not be given to pregnant or breastfeeding women until more data is available. These judgements reflect the absence of data at the present time and do not reflect a specific finding of concern. Further studies on this are planned, the results of which will be provided when available, and the guidance will be changed accordingly – if appropriate.”
That is standard with any new medication or vaccine, but these aren’t normal times. In recognition of that, US regulators – both the Food and Drug Administration (FDA) and CDC – have approved the use of the vaccine in pregnant people who are otherwise at risk, telling Pfizer to track its safety in pregnant women. Canada’s regulator has followed a similar route, saying that if a risk assessment deems the benefits of the vaccine outweigh the risks for the mother or the fetus, then the jab may be offered.


That leaves pregnant and breastfeeding women in the UK without access to the same vaccine that their peers across the Atlantic could get – potentially problematic as so many frontline workers are women, including 77 per cent of the NHS workforce, and pregnancy is a common state for women, with 839,043 recorded conceptions across England and Wales in 2018 alone.
And those women need protection from Covid-19. “They’re in a clinically vulnerable group,” says Lucy Chappell, research professor in obstetrics at King’s College London. “They’re asked to minimise their contacts. And the relevance of that is it has a direct impact on their maternity care, on how services are provided, and an indirect effect on their mental health.”
While it’s the norm to leave pregnant women out of vaccine trials, they do get jabs while gestating, in particular for the flu and whooping cough. “There aren’t any intrinsic, biological reasons why women should not be included in vaccine options,” Chappell says. Pregnant women are already told not to get any live-attenuated virus vaccines, because of the potential risk they could infect the unborn child. But even that is largely theory: a review of studies of such vaccines suggests only the chickenpox jab poses a real threat, though it’s clear more research is needed – and, to be clear, the MHRA can be expected to quickly update its advice when that research is available. “The UK is fairly good with vaccines,” adds Kirsty Le Doare, professor of vaccinology and immunology at St George’s, University of London (SGUL). “It was the first to introduce the hepatitis B vaccine for pregnant women.”
While we have no safety data either way about new vaccine types and their impact on pregnant women, we also can’t actually imagine how they would be harmful, beyond common side effects such as fever, which can be damaging to the fetus but can be controlled using paracetamol. The CDC notes the Pfizer/BioNTech vaccine does not use a live virus – indeed, that’s one reason it’s well placed to treat older, ill people – and the MHRA stresses it sees no specific concern.


Part of the problem is the first two vaccines from Pfizer/BioNTech and Moderna use an entirely new way of producing vaccines. That means caution is a “good way forward,” says Le Doare, though she adds that similar virus vector vaccines, such as one developed for Ebola, were used on pregnant women without any adverse effects. But older, better studied vaccine candidates that use more familiar techniques, such as Valneva and Novavax, could be a better choice, especially in the early days – however, both are still working their way through trials so they don’t help people who are pregnant now.
This is why pregnant women are told to wait for a different vaccine or more data. But it’s worth noting that the MHRA is not just treating pregnancy as a reason to withhold treatment, it’s doing the same for breastfeeding, treating both subgroups as though they have the same concerns. This has angered some doctors, who are demanding changes from regulators in particular to the vaccine ban for those who are breastfeeding. “There’s a huge amount of doctors and nurses that are concerned they’re not getting vaccinated on the basis that they’re lactating,” says one healthcare worker, who asked to remain anonymous.
That pregnancy and breastfeeding aren’t the same may sound obvious, but those two subgroups of people are often treated as such for medical purposes.”We’ve been talking to breastfeeding doctors who are really concerned that they feel under pressure to either stop breastfeeding or put themselves at risk of Covid-19,” says Joeli Brearley, founder of Pregnant Then Screwed, a group that campaigns against pregnancy and maternity discrimination. All of that said, while giving women at a higher risk of Covid the right to choose to access this particular vaccine or not may have merit, it also raises other issues. “Then we’ll have pressure from bosses to pregnant women saying: you’ve been given a choice, it’s up to you,”says Brearley. “It’s not fair to put them under that pressure.”
Indeed, how can anyone – the MHRA or pregnant women – make such a serious decision without information? That’s the core problem: pregnant women are given very little data. And the gap in advice and serious information is being filled by conspiracy theories online spreading misinformation about fertility – with some posts pointing to the MHRA’s own statements as “evidence” the vaccine isn’t safe, when that’s not at all what it says.
But we could get more data soon. According to the New York Times, Pfizer is expected to file data from animal trials before the end of 2020. That developmental and reproductive toxicity (DART) study is normally required for a full license, but not for the vaccine to be approved under an Emergency Use Authorisation, the report adds. WIRED asked AstraZeneca, Moderna, BioNTech and the University of Oxford about such studies, but none responded to requests for comment on this story. Pfizer said it doesn’t currently have a study in pregnant women but was following FDA guidance on the issue.
That data could help give some direction to the tough decisions set to be made by pregnant American and Canadian women, as could a careful examination of the theoretical risks. “What we need to do is, one by one, look at the mode of action of the vaccine and what we know and what we don’t know,” says Chappell. “You can take the American approach of ‘is it reasonable to implement based on theoretical knowledge’? Or [the UK approach] of ‘is it reasonable to [wait for] the research’?”
The answer will come down to how at risk pregnant women are – and that depends person-by-person on where they live, their job, and so on – and how safe we theoretically assume the vaccine to be. The risk could also shift with time: Chappell notes that women in their third trimester are at most at risk from Covid-19, and that point could be the safest for the fetus as the organs are already fully formed. That risk/reward balance could mean it makes most sense for pregnant women to wait until the third trimester to get the vaccine, giving time for an alternative to be released or more safety data to be collected, as well.
While we await more formal trials, we do get some additional data on vaccines and human pregnancies by accident. During the vaccine trials, some women got the jab not knowing they were pregnant, and that will happen throughout the vaccine rollout; your GP won’t ask you to take a pregnancy test before sticking you in the arm, after all. This data is collected throughout the rollout and will act as our de facto trial in pregnant women – it’s deemed unethical to test on willing pregnant women or to give the jab to willing pregnant women, leaving those with unexpected pregnancies to bear the data burden. “You will find with the vaccine that’s just been licensed that people will have the vaccine and they won’t know they’re pregnant or become pregnant, and in six to 12 months you will have the safety data that shows it’s safe,” says Le Doare.
In the meantime, women who are pregnant or breastfeeding are left without protection against Covid-19, and those planning to start a family are being told to hold off until they get both shots of the vaccine; the government claims this will happen by April.
It could have been different. Chappell started asking colleagues back in August what consideration was being taken around pregnancy and breastfeeding. “Everyone’s work was so full up that they sort of said: not yet,” she says. “We’ve had to bide our time.” As SGUL’s Le Doare notes, in the early stages of the pandemic it was believed pregnant women weren’t at higher risk, though subsequent data changed that assumption.
While it’s perhaps forgivable given the havoc of this year, medical science has long failed to include pregnant women in trials. “My understanding is that this is the problem generally with drug companies, the paucity of data creates all sorts of problems and women are advised not to take drugs that they can take and vice versa,” Brearley says. “They’re just not prioritised.”
Asked why she thinks that is, Brearley has a clear answer. “It’s sex discrimination,” she says, noting that drug companies treat men as the default. “Female bodies […] particularly when they’re doing something seen as unusual such as lactating or pregnancy, [are]seen as too complicated,” she says. “It’s just a subgroup, it’s too complicated, it’s not the norm – it’s not seen as the norm to get pregnant and have kids.”
What could be done now? We need vaccines from tried and tested technologies to win backing and approval, and we need other treatments to be prioritised for groups who can’t get vaccines, including pregnant women. Chappell points to the Valneva vaccine, which is a tried-and-tested inactivated technology due for regulator approval mid-2021 as well as neutralising antibodies, an expensive and experimental therapy to reduce negative Covid-19 outcomes. We need existing data, be it from animals or accidental pregnancies during trials, to be analysed and released with the speed and diligence of the overall trial data. We need to know when to expect that data, and what we’re waiting on — two questions the MHRA could not answer, though such detail could help women make better choices. It may not be worth taking the risk of a jab now if safety data is due in a month, for example. And we need pharmaceuticals and regulators to stop treating pregnant and breastfeeding women as one and the same.
None of that is asking too much, and none of it means pregnant women should necessarily take this vaccine. Pregnant women deserve what Chappell calls an “exit strategy” – because telling all pregnant women to stay home for the next two years doesn’t work. “If you put them in a clinically vulnerable group, you need an exit strategy,” says Chappell. “And that exit strategy should be equitable access to vaccine research.”
More great stories from WIRED
🏥 The devastating human cost of a mental health data breach
🇷🇺 Russia’s vaccine has attracted criticised. Here’s what is really happening with the Sputnik V vaccine
🍿 The Netflix Christmas Cinematic Universe is being torn apart


🔊 Listen to The WIRED Podcast, the week in science, technology and culture, delivered every Friday
👉 Follow WIRED on Twitter, Instagram, Facebook and LinkedIn

Like this article?

Share on Facebook
Share on Twitter
Share on Linkdin
Share on Pinterest

Leave a comment

Why You Need A Website