MHRA update on COVID-19

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Medicines and Healthcare products Regulatory Agency bulletin

Dear Colleague,

This email updates you on details of recently published MHRA guidance on the coronavirus (COVID-19) pandemic aimed at supporting healthcare partners.


Safety reports of approved COVID-19 vaccines

We have published our weekly safety reports for approved COVID-19 vaccines and you can access the report here.


Reports of menstrual disorders and unexpected vaginal bleeding following COVID-19 vaccination

We have reviewed reports of menstrual disorders and unexpected vaginal bleeding suspected as adverse reactions to vaccination with the three COVID-19 vaccines currently being used in the UK: Pfizer/BioNTechCOVID-19 Vaccine AstraZeneca and COVID-19 Vaccine Moderna. These reports have also been reviewed by independent experts of the Commission on Human Medicines’ COVID-19 Vaccines Benefit Risk Expert Working Group and members of its Medicines for Women’s Health Expert Advisory Group.

A range of menstrual disorders has been reported as suspected adverse reactions after all three of these COVID-19 vaccines including heavy bleeding, delayed periods and unexpected vaginal bleeding. The number of reports of menstrual disorders and vaginal bleeding is low in relation to both the number of females who have received COVID-19 vaccines to date and the background rate of menstrual disorders generally.

The current evidence does not suggest an increased risk of either menstrual disorders or unexpected vaginal bleeding following vaccination with the vaccines reviewed (Pfizer/BioNTech, COVID-19 Vaccine AstraZeneca or COVID-19 Vaccine Moderna). Our advice remains that the benefits of the vaccine outweigh the risks for most people. We will continue to closely monitor reports of suspected menstrual disorders and vaginal bleeding with COVID-19 vaccines.

Healthcare professionals are advised that anyone presenting with menstrual disorders and/or unexpected vaginal bleeding following COVID-19 vaccination should be treated according to clinical guidelines for these conditions, as usual.

As with any suspected side effects from the COVID-19 vaccines, including those in relation to menstrual disorders, please continue to report via the Yellow Card scheme here.


Personal Protective Equipment and heat: risk of heat stress

Wearing personal protective equipment (PPE) in warm/hot environments increases the risk of heat stress. This occurs when the body is unable to cool itself enough to maintain a healthy temperature. Heat stress can cause heat exhaustion and lead to heat stroke if the person is unable to cool down.

Measures to control the temperature of clinical environments and enable staff to make behavioural adaptations to stay cool and well hydrated should be made. Staff may require more frequent breaks and the frequency of PPE changes may increase, with a resulting increase in demand.

See the Chief Medical Officers (CMO’s) alert for further information and action.


Guidance for industry

We continue to update our guidance page for industry on GOV.UK as our response to COVID-19 evolves.

Subscribing to updates on GOV.UK

You can sign up for email updates about the MHRA’s work – you will then receive an email every time the MHRA publishes a new page or makes a significant edit to an existing page.

Contacting the MHRA

Most of our workforce is working from home, although National Institute for Biological Standards and Control (NIBSC) is continuing essential laboratory activities on site. If you need to get in touch with the MHRA during this period, please email or phone 0203 080 6000.

For more information please visit

We welcome your feedback on what other information you would find useful – please email

Thank you.


Patient, Public and Stakeholder Engagement team
The Medicines and Healthcare products Regulatory Agency

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