Understanding the VAERS data format

VAERS consists of three CSV files: DATA, SYMPTOMS and VAX

Data CSV file

The data CSV file has the most amount of information.

You can see the following columns in the DATA CSV file.

1 VAERS_ID
2 RECVDATE
3 STATE
4 AGE_YRS
5 CAGE_YR
6 CAGE_MO
7 SEX
8 RPT_DATE
9 SYMPTOM_TEXT
10 DIED
11 DATEDIED
12 L_THREAT
13 ER_VISIT
14 HOSPITAL
15 HOSPDAYS
16 X_STAY
17 DISABLE
18 RECOVD
19 VAX_DATE
20 ONSET_DATE
21 NUMDAYS
22 LAB_DATA
23 V_ADMINBY
24 V_FUNDBY
25 OTHER_MEDS
26 CUR_ILL
27 HISTORY
28 PRIOR_VAX
29 SPLTTYPE
30 FORM_VERS
31 TODAYS_DATE
32 BIRTH_DEFECT
33 OFC_VISIT
34 ER_ED_VISIT
35 ALLERGIES

You can read the descriptions for these columns here.

Symptoms CSV file

The SYMPTOMS CSV file has information about the symptoms which were coded based on the VAERS report.

Note: you can have multiple rows of symptoms for a given VAERS_ID

You can see the following columns in the SYMPTOMS CSV file:

1 VAERS_ID
2 SYMPTOM1
3 SYMPTOMVERSION1
4 SYMPTOM2
5 SYMPTOMVERSION2
6 SYMPTOM3
7 SYMPTOMVERSION3
8 SYMPTOM4
9 SYMPTOMVERSION4
10 SYMPTOM5
11 SYMPTOMVERSION5

Vaccine CSV file

The VAX CSV file has information about the vaccines which were administered to the patient, including past vaccines.

Note: you can have multiple rows of vaccines for a given VAERS_ID

You can see the following columns in the VAX CSV file:

1 VAERS_ID
2 VAX_TYPE
3 VAX_MANU
4 VAX_LOT
5 VAX_DOSE_SERIES
6 VAX_ROUTE
7 VAX_SITE
8 VAX_NAME

Important fields

Some important fields in VAERS DATA CSV file:

VAERS_ID

This is the VAERS identification number which is assigned to each report.

Symptom text

This is the text writeup included in each VAERS report and has a lot of information which is used to populate the other fields in the CSV file.

Adverse Event Outcomes

There are many fields in VAERS used to denote outcomes

DIED – did the patient die? (Yes or No)

HOSPITAL – was the patient hospitalized? (Yes or No)

HOSPDAYS – number of days hospitalized (int) if any

XSTAY – required an extended stay at the hospital

L_THREAT – did they experience a life threatening adverse event? (Yes or No)

DISABLE – did the patient develop some disability? (Yes or No)

ER_ED_VISIT – did the adverse event require a visit to the ER room or the Emergency Department? (Yes or No)

RECOVD – did the patient fully recover from all symptoms (Y = Yes, N = No, U = Unknown)

Date fields

VAX_DATE – date of vaccination (For which the adverse event was reported, and this must be the most recent date of vaccination for a multi-dose vaccine like the COVID19 vaccine)

ONSET_DATE – date of earliest symptom onset

DATEDIED – date of death if applicable

RECVDATE – when was this VAERS reported first received?

RPT_DATE – this is often empty, but this is the date the form was filled out and submitted to the online VAERS system

Patient history

OTHER_MEDS – Other medications the patient was taking

CUR_ILL – Illnesses at time of vaccination

HISTORY – Chronic or long-standing health conditions

PRIOR_VAX – Prior vaccination event information

BIRTH_DEFECT – Congenital anomaly or birth defect

ALLERGIES – Allergies to medications, food, or other products

Patient demographics

STATE – state where patient resides
AGE_YRS – Age in years
CAGE_YR – Calculated age of patient in years
CAGE_MO – Calculated age of patient in months
SEX – Sex

Other fields

LAB_DATA – Diagnostic laboratory data

V_ADMINBY – Type of facility where vaccine was administered (this is often left empty)

V_FUNDBY – Type of funds used to purchase vaccines (this is also often left empty)

SPLTTYPE – Manufacturer/immunization project report number (you can usually infer the country if this field is filled out)