Covid-19 Vaccine - Frequently Asked Questions (FAQs)

Safety and Clinical Trials

Can you catch COVID-19 from the vaccine?

You cannot catch COVID-19 from the vaccine but it is possible to have caught COVID-19 and not realise you have the symptoms until after your vaccination appointment.

Is the NHS confident the vaccines are safe?

Yes. The NHS will not offer any Covid-19 vaccinations to the public until independent experts have signed off that it is safe to do so.  

The MHRA, the official UK regulator, have said that both of these vaccines have good safety profiles and offer a high level of protection, and we have full confidence in their expert judgement and processes.

As with any medicine, vaccines are highly regulated products.

Blood clot reports

There have been reports of extremely rare blood clots after the Oxford/AstraZeneca COVID-19 vaccine. The current risks are currently equivalent to approximately 4 people in every million vaccination doses.

The MHRA have now advised that those who are eligible under 40 (if you have an underlying health condition, or you are a frontline worker) should be offered an alternative vaccine to the AstraZeneca vaccine where available. If you are a frontline health or social care worker, please click here for more information. If you have an underlying condition, please contact your GP for information on how to book your vaccine.

For those who are over the age of 40, you are still advised to utilise the AstraZeneca vaccine as it is safe. If you have had a first dose of AstraZeneca, you should continue to have your second dose. You should not mix vaccines unless in extreme circumstances.

It is considered safe because the risk of severe effects from the vaccine is significantly lower than the risk of severe effects from a COVID-19 infection for those adults who are currently eligible for vaccination.

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How were vaccines developed so quickly?

Medicines including vaccines are highly regulated – and that is no different for the approved COVID-19 vaccines. There are a number of enablers that have made this ground-breaking medical advancement possible and why it was possible to develop them relatively quickly compared to other medicines;

  1. The different phases of the clinical trial were delivered to overlap instead of running sequentially which sped up the clinical process. 
  2. There was a rolling assessment of data packages as soon as they were available so experts at the MHRA could review as the trial was being delivered, ask questions along the way and request extra information as needed – as opposed to getting all information at the end of a trial; 
  3. Clinical trials managed to recruit people very quickly as a global effort meant thousands of people were willing to volunteer. 

Were the trial participants reflective of a multi-ethnic population?

The Public Assessment Reports contain all the scientific information about the trials and information on trial participants.

For the Pfizer trial, participants included 9.6% Black/African, 26.1% Hispanic/Latino and 3.4% Asian.

For the Oxford/AstraZeneca vaccine 10.1% of trial recipients were Black and 3.5% Asian.

For the Moderna vaccine, 9.7% of the trial recipients were Black and 4.7% Asian.

There is no evidence any of the vaccines will work differently in different ethnic groups.

Were the vaccines tested on high-risk groups?

For both vaccines trial participants included a range of those from various ages, immune-compromised and those with underlying health conditions, and both found the efficacy of the vaccine translates through all the subgroups.

Details of trial participants for both vaccines are published online.

There are checks at every stage in the development and manufacturing process and continued monitoring once it has been authorised and is being used in the wider population.    


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