Yellow CARD analysis

Data is a precious thing and will last longer than the systems themselves.

– Tim Berners-Lee


Our analysis of the Medical & Healthcare products Regulation Agency (MHRA) Yellow Card Scheme for COVID-19 vaccines uses the publicly available weekly reports that are released by the MHRA.  Regrettably, the MHRA overwrites the report each week, so the only download available to the general public at any given time is the summary at that particular point.  Without access to preceding reports, the snapshot their document provides allows for little analysis.

Fortunately, we have managed to obtain copies of every weekly report going back to the start of the COVID-19 vaccine rollout and have therefore been able to build a more detailed picture of how adverse reactions have developed over time.

The MHRA does a weekly “cut off” of data but then takes several days to make the summary report available on its website.  So at times we can be looking at information that is two weeks out of date.  Given that millions are receiving vaccines each week, we are concerned that this time lag introduces additional risk as well as restricting the ability of an individual to make a truly informed decision about having the vaccine based on up to date risk information.

We are also hampered by incomplete data so have deliberately held back from drawing conclusions based on the data we have.  Instead, we aim to provide insights into what we do know so that we, and you, can ask more meaningful questions of the MHRA, the government, vaccine manufacturers – and your own healthcare providers.   

What We Do Know

What We Don't Know

Cause for Concern

As we began our first look at the week by week data, it came to our attention that Dr Tess Lawrie (MBBCh, PhD), of the Evidence-based Medicine Consultancy, was about to undertake a similar task.  We therefore reached out and agreed that we would pool our technical skills and her medical expertise to better understand and analyse the data.

An important discovery was that similar conditions had been classified in many different ways.  Dr Lawrie’s medical knowledge helped us to better group similar conditions together.  Once we did that, it became clear that there were far higher incidences of some reactions than a cursory glance of the MHRA report would suggest.

Dr Lawrie was so concerned about what she saw that she immediately presented the findings in an open letter to Dr June Raine, Chief Executive of the MHRA.  As well as presenting the findings, the letter also calls for an immediate halt of the COVID-19 vaccine rollout until more detailed analysis of the Yellow Card data can be carried out.     

Yellow Card Summary to 1st September 2021

Pfizer/ BioNTech AstraZeneca Moderna Unspecified Totals
Rollout Start Date 08/12/20 04/01/21 07/04/21 n/a n/a
First Doses Administered 21.9 million 24.8 million 1.4 million n/a 48.1 million
Second Doses Administered 18.1 million 24.1 million 0.9 million n/a 43.1 million
Adverse Reactions 314,700 820,923 47,977 3,244 1,186,844
Deaths 524 1,064 16 28 1,632

New reactions this week = 8,775

New deaths this week = 20

Data Source: MHRA

How The Brands Compare


Adverse Reactions


Top 20 Adverse Reactions

wdt_ID Condition No of Reactions No of Deaths
1 Headache 104,549 0
2 Fatigue 69,745 0
3 Pyrexia 68,961 1
4 Chills 51,749 0
5 Nausea 46,062 0
6 Myalgia 36,518 0
7 Pain in extremity 33,619 0
8 Dizziness 31,627 0
9 Arthralgia 30,498 0
10 Pain 25,073 0

Top 20 Causes of Death

wdt_ID Condition No of Deaths
1 Death (no further information available) 459
2 Pulmonary embolism 125
3 Myocardial infarction 84
4 Cardiac arrest 67
5 Sudden death 63
6 COVID-19 61
7 Cerebrovascular accident 58
8 Cerebral haemorrhage 54
9 Pneumonia 41
10 Thrombosis 40

Vaccine Rollout by Week

Further analysis coming soon

In the meantime, if you'd like to find out more about COVID-19 vaccines, the Public Health England weekly surveillance reports may prove useful:

If you'd like to find out about adverse reactions recorded in other countries, here are some useful links: