Observed vs. expected rates

The GVDN Observed vs. Expected Dashboard below compares the occurrence of adverse events of special interest (AESI) from different sites/countries and population subgroups (age and sex) on a set of consistently defined AESI after the introduction of COVID-19 vaccines with the number of expected events based on background rates measured over 2015–2019 in the same population subgroups, prior to the SARS-CoV-2 virus (COVID-19 disease) outbreak and introduction of COVID-19 vaccines. 

The Dashboard also presents data, under the Global data (meta-analysis) site, from meta-analyses of the combined (aggregated) observed vs. expected rates of AESI reported by the GVDN sites/countries. The use of common protocols across the sites/countries harmonises the approach to collection, collation, and analyses of data. This allows aggregation of the results from the locally measured observed number of cases compared with the number of expected events based on background rates measured over 2015–2019 in the same local population subgroups, prior to the SARS-CoV-2 virus (COVID-19 disease) outbreak and introduction of COVID-19 vaccines.

Click on this link to visit the Background Rates Dashboard on our website.

Click on this link to download the GVDN Observed vs. expected analyses of COVID-19 vaccine adverse events of special interest study protocol

Click on this link to view the paper COVID-19 vaccines and adverse events of special interest: A multinational Global Vaccine Data Network (GVDN) cohort study of 99 million vaccinated individuals published in the journal Vaccine.

Ten GVDN member sites in eight countries followed the protocol above and analysed data from national or regional healthcare databases covering 99 million people from Europe, Asia, North and South America, and Oceania. Meta-analyses of the observed rates of adverse events of special interest after COVID-19 vaccine introduction compared with the expected (background) pre-COVID-19 vaccine rates established in the GVDN Background Rates Study that includes such a large, diverse population increases the statistical power to identify rare but potential vaccine safety signals to inform when further investigation is required and enhances generalisability of what is known about vaccine safety.

 Click on this link to view the accompanying paper Acute disseminated encephalomyelitis and transverse myelitis following COVID-19 vaccination – A self-controlled case series analysis published in the journal Vaccine.
The GVDN site in Victoria, Australia conducted a self-controlled case series study including 6.7 million vaccinated individuals to determine the relative incidence of two neurological adverse events of special interest following receipt of a COVID-19 vaccine.
 

You will need Adobe Acrobat Reader to open the study protocol.


Brief guide for using the dashboard

After selecting the site from a dropdown menu, data can be viewed in graph or table format by AESI and patient type as combined data, or by age, sex, or age-sex, and by year(s). Information describing the site, data source(s), active population, and patient type has been provided by each site and is available in the third tab.

 Use the lower scroll bar to view all the dashboard options. 

To resize the dashboard to fit within your viewing screen, click in the dashboard area, then hold down the Control button on your keyboard and scroll up or down.

Clicking on the question icon beside each data set provides additional information related to the variables in that set. 

In the graph view, tab one, clicking on the camera icon will download a picture (PNG) file of the plot. It is possible to zoom into the plot, click and hold the right mouse button while drawing a marquee around the area of the plot you wish to zoom into, then release the button. Clicking on the house icon will reset the plot axes. While in the graph view, hovering the mouse over a data point will show the closest data numerically.

Data provided in the table view can be downloaded as a spreadsheet (XLXS) file by clicking on this button .

In tab three, information describing the site, data source(s), active population, and patient type has been provided by each site.

The data dashboard will time-out and the screen will become grey if the dashboard is left idle for too long. Refreshing the webpage will activate the dashboard again and previous data selections will need to be re-entered.

 Use the scroll bar below to view all the dashboard options.