When you’re pregnant, it’s understandable that you might feel cautious. After all, you’re told to avoid all sorts of things – soft cheeses, alcohol, certain medications – because they could be bad for the baby. You might find it surprising to be recommended a medical treatment that is still quite new. This partly explains why levels of Covid vaccination during pregnancy still seem to be relatively low. In August 2021, only 22% of those who gave birth had received the Covid vaccine. This leaves them and their babies at risk: between May and October 2021, 96% of those admitted to hospital with Covid symptoms while pregnant were unvaccinated. In response, the government has launched a campaign urging anyone who is pregnant to “get boosted now”. It’s an important step, given that a Covid infection doubles the chances of a baby being born pre-term and roughly triples the chances of stillbirth. But it has taken a long time to get here, and the messaging around pregnancy and Covid vaccines so far has added to the reluctance among those who are pregnant to get the vaccine. We now have a great deal of evidence that getting the vaccine does not increase the risk of experiencing a pregnancy complication. But back in December 2020, when the vaccines were first approved, there had been no clinical trials in pregnancy, so the government decided it wouldn’t offer the vaccines to pregnant people at all. It quickly became clear that this was a problem, as many who were pregnant were also at high risk from Covid – either because they had preexisting conditions or because they were healthcare workers who would be highly exposed to the virus. This led to a change in the policy only a couple of weeks later, allowing those who were high-risk to receive any of the approved vaccines. At this point, it didn’t matter on a practical level that they weren’t available to others who were pregnant – they weren’t being offered to most under-50s anyway. However, it set a tone of caution around Covid vaccines and pregnancy. And crucially, when the rules were changed again in April to allow anyone who was pregnant to receive either the Pfizer or Moderna vaccine along with their age group, the government stopped short of actually recommending that they do so. By then, we had data on the safety of Covid vaccines in pregnancy, but many people didn’t know where to look for it. This is where I started trying to close the information gap, using social media to speak directly to those making this decision for themselves and their babies. It wasn’t until July 2021 that the Royal College of Obstetricians and Gynaecologists (RCOG) changed its policy from “we’re offering it” to “we’re recommending it”. And it wasn’t until December that The Joint Committee on Vaccination and Immunisation finally began to prioritise those who are pregnant for the vaccine. Although these gradual shifts in policy reflect the way in which evidence has built up, these drip-by-drip changes have, in my experience, had a real effect on the view of the vaccine. Many ordinary people have tuned into the message once, and the first thing they hear remains with them. Last August, when I was speaking to pregnant patients, I would say, “It’s safe, it protects you and your baby, and the RCOG recommends that you get it,” and they would respond, “But I was talking to someone in February and they told me not to.” Worse still, the changes in policy weren’t always communicated at ground level, with some of those who were eligible for the vaccine being turned away from vaccination centres because they were pregnant. A useful point of comparison is Canada, which initially only offered the vaccine to high-risk pregnant people, then extended it to everyone in the same month as the UK. But the Canadian authorities decided that if there was enough evidence to offer the vaccine to someone, there was enough evidence to recommend it. When the policy changed, they came out strongly with a message calling for anyone who was pregnant to come forward to protect themselves and their baby. As a result in Ontario, by September 2021, almost 60% of them were vaccinated against Covid. The UK didn’t come out with a confident message at first, which has left us struggling to get vaccination rates up. Meanwhile, the job has been made harder by those who are actively spreading misinformation about the safety of the vaccines. However, I hope that the trusted voices of the NHS and RCOG behind this new campaign will give those who are making this decision confidence that these vaccines are safe in pregnancy and are the best way to protect themselves and their babies from the potentially devastating consequences of Covid. Viki Male is a lecturer in reproductive immunology at Imperial College London