Data Overview

Available datasets

The workspace includes several CSV files related to vaccination records and surveys:

• covid_daily_survey.csv
• covid_dose_history.csv
• covid_enrollment.csv
• covid_vaccination.csv
• covid_vaccination_old_records.csv
• covid_weekly_survey.csv

How the analysis data were prepared

The website does not analyze the CSV files separately. It first converts the daily survey into a participant-level table and then joins that table to the vaccination records using VSAFE_SYSTEM_ID.

• The daily survey file is cleaned to keep only yes/no symptom responses.
• A participant-level symptom_free variable is created from the daily survey history. It equals 1 only when that participant has no yes symptom responses in the available daily rows.
• The participant-level daily table is joined to covid_vaccination.csv on VSAFE_SYSTEM_ID so age band, dose number, and current health state are available in one analysis table.
• Rows with invalid age values or missing join fields are removed.
• For the main analysis, Fourth and Fifth doses are excluded because they are extremely sparse and would not give stable comparisons.
• Missing key fields are dropped rather than imputed.

Cleaning summary

Table 1

	step	records
0	Daily survey rows after dropping missing sympt...	139421
1	Participant-level records created from daily s...	31630
2	Rows after joining vaccination records	37246
3	Final analysis sample after removing invalid a...	37233

Enrollment and vaccination trends

The data shows a sharp spike in enrollment during early 2024 and again toward late 2024, while most records are concentrated in first and second dose activity.

Enrollment trend chart

Monthly enrollment trend

Dose distribution chart

Dose number distribution

Summary table

Metric	Value
Enrollment records	91,379
Vaccination records	91,216
Daily survey responses	139,421
Weekly survey responses	220,416
Most common manufacturer	Pfizer-BioNTech
Most common dose	First

Interpretation

• Enrollment activity is seasonally uneven, but the dataset is dominated by a small number of intense reporting periods.
• First-dose records account for most vaccination entries, suggesting a large share of the sample is still captured at the initial dose stage.
• The summary table gives a concise snapshot that can be expanded with more participant-level drilldowns later.