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  So at times we can be looking at information that is two weeks out of date.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 called for an immediate halt of the COVID-19 vaccine rollout until more detailed analysis of the Yellow Card data can be carried out. 

With the rollout continuing, Dr Lawrie sent a follow up letter in September 2021 highlighting even more concerns, particularly that the suspected deaths per million doses was 28 times higher than for the flu vaccines.   

Yellow Card Summary to 8th June 2022

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 26.9 million 24.9 million 1.7 million n/a 53.5 million
Second Doses Administered 24.4 million 24.1 million 1.5 million n/a 50.0 million
Boosters Administered 39.8 million 39.8 million
Adverse Reactions 493,622 869,745 130,280 5,344 1,498,991
Deaths 789 1,286 60 47 2,182

New reactions this week = 4,368

New deaths this week = 34

Data Source: MHRA

How The Brands Compare


Adverse Reactions


Due to the way MHRA reports booster doses without a breakdown between the brands used, there is a growing disconnect between brand dosage numbers and adverse reactions. While booster doses are shown under "Unspecified", the likelihood is that people reporting a reaction are specifying which brand they received. It is therefore increasingly difficult to draw any meaningful conclusions. We still await an explanation as to why MHRA are not reporting booster doses by brand in the same way they report first and second doses.

Top 20 Adverse Reactions

wdt_ID Condition No of Reactions No of Deaths
1 Headache 121,373 1
2 Fatigue 84,967 1
3 Pyrexia 79,997 1
4 Chills 58,270 0
5 Nausea 54,159 0
6 Myalgia 42,601 0
7 Pain in extremity 41,866 2
8 Dizziness 37,913 0
9 Arthralgia 37,046 0
10 Pain 31,154 0

Top 20 Causes of Death

wdt_ID Condition No of Deaths
1 Death (no further information available) 562
2 Pulmonary embolism 167
3 Myocardial infarction 113
4 Cardiac arrest 93
5 Cerebrovascular accident 77
6 Sudden death 76
7 Cerebral haemorrhage 75
8 COVID-19 74
9 Pneumonia 57
10 Thrombosis 54


wdt_ID Type of Reaction (System of Care) Reactions Deaths
1 Blood disorders 27,637 24
2 Cardiac disorders 28,572 384
3 Congenital disorders 232 3
4 Ear disorders 18,963 1
5 Endocrine disorders 944 0
6 Eye disorders 24,873 0
7 Gastrointestinal disorders 135,804 35
8 General disorders 420,002 706
9 Hepatic disorders 879 11
10 Immune system disorders 6,676 8

Vaccine Rollout by Week

Weeks with negative doses are not our error but are where the totals contained in the MHRA reports are lower than the preceding week. We do not know if this is due to a clerical error in the preparation of the current weekly report, a correction of clerical errors made in previous reports or a correction due to errors in the past reporting of doses to the MHRA.

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: