Pregnant women or women planning a pregnancy should not receive a coronavirus vaccine because any potential risks are still unknown, new guidance says.
The Joint Committee on Vaccination and Immunisation (JCVI) updated its advice on priority groups for vaccination after the UK approved Pfizer's jab for emergency use on Wednesday.
The JCVI recommended pregnant women not come forward to receive the jab, writing: "There are no data as yet on the safety of Covid-19 vaccines in pregnancy, either from human or animal studies.
"Given the lack of evidence, JCVI favours a precautionary approach, and does not currently advise Covid-19 vaccination in pregnancy.
"Women should be advised not to come forward for vaccination if they may be pregnant or are planning a pregnancy within three months of the first dose."
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It adds: "Data are anticipated which will inform discussions on vaccination in pregnancy.
"JCVI will review these as soon as they become available."
The JCVI, which advises the Government, set out its guidance for priority groups ahead of a mass vaccination campaign that will begin next week when Britain receives its first shipment of the Pfizer vaccine.
The elderly, vulnerable and health and social care workers will be given priority.
The guidance does not include pregnant women or children under 16.
The JCVI said further research is being carried out to understand the safety of Covid-19 vaccines in pregnancy and children.
It said: "As trials in children and pregnant women are completed, we will also gain a better understanding of the safety and effectiveness of the vaccines in these persons."
It also said "only those children at very high risk of exposure and serious outcomes... should be offered vaccination".
Who gets priority?
The JCVI said care home residents were among those who should be given the jab first.
The committee examined data on who suffers the worst outcomes from coronavirus and who is at highest risk of death.
It published interim guidance earlier in the year, but this has now been amended slightly.
In the new guidance, those who are deemed to be "clinically extremely vulnerable" have moved higher up the priority list.
The priority list for "phase one" of the Covid-19 vaccination programme is:
1. Residents in a care home for older adults and their carers
2. All those 80 years of age and over and frontline health and social care workers
3. All those 75 years of age and over
4. All those 70 years of age and over and people deemed to be clinically extremely vulnerable.
5. All those 65 years of age and over
6. All individuals aged 16 years to 64 years with underlying health conditions which put them at higher risk of serious disease and mortality
7. All those 60 years of age and over
8. All those 55 years of age and over
9. All those 50 years of age and over
Wei Shen Lim, of the JCVI, set out the thinking behind the priority list drawn up by the body.
He told a Downing Street briefing: "Prioritisation was based on the risk of dying from Covid-19 and, in order to protect the most vulnerable, we have prioritised the most vulnerable individuals first.
"The other element is protection of the NHS and the health and social care system, because by protecting the NHS we also protect lives."
He said prioritisation was needed because of the limited availability of the vaccine, adding: "The whole reason why a priority listing is required is because we expect, during a pandemic, that vaccine supply will be limited in the first instance."
The UK and the wider world will need "as many vaccines as we can get" in order to reach all those at risk.
"This is the start of a programme and not the end of a programme," he said.
Advice for children
The JCVI wrote: "Following infection, almost all children will have asymptomatic infection or mild disease.
"There are very limited data on vaccination in adolescents, with no data on vaccination in younger children, at this time.
"The Committee advises that only those children at very high risk of exposure and serious outcomes, such as older children with severe neuro-disabilities that require residential care, should be offered vaccination.
"Clinicians should discuss the risks and benefits of vaccination with a person with parental responsibility, who should be told about the paucity of safety data for the vaccine in children aged over 16 years."
UK through Covid-19 'by spring'
As it emerged on Wednesday that the UK has approved the Pfizer and BioNTech vaccine, Health Secretary Matt Hancock declared Britain will be through Covid-19 "by spring".
The jab has been shown in studies to be 95% effective and works in all age groups.
The UK has ordered 40million doses of the Pfizer vaccine, enough to vaccinate 20million people - or about a third of the population - with two doses, given 21 days apart.
Around 10million doses are expected to be available for use in the UK in the coming weeks for priority groups, including healthcare workers, with 800,000 doses arriving next week.
Vaccines developed by Moderna and AstraZeneca/Oxford University could be given emergency use approval soon.
The UK has secured access to 100million doses of the AstraZeneca/Oxford University vaccine, which is almost enough for most of the population.
It also belatedly struck a deals for seven million doses of the jab on offer from Moderna in the US.
The deals cover four different classes: adenoviral vaccines, mRNA vaccines, inactivated whole virus vaccines and protein adjuvant vaccines.
The UK has secured access to:
- 100million doses of the Oxford vaccine
- 60million doses of the Novavax vaccine
- Some 30million doses from Janssen
- 40million doses of the Pfizer/BioNTech vaccine - the first agreement the firms signed with any government
- 60million doses of a vaccine being developed by Valneva
- 60million doses of protein adjuvant vaccine from GlaxoSmithKline (GSK) and Sanofi Pasteur
- Seven million doses of the jab on offer from Moderna in the US.
