Covid-19 Vaccine Tracker Frequently Asked Questions

Where do you get your data?

The data powering the vaccine tracker comes from countries, provinces and their official representatives, as well as non-government organizations including the World Health Organization, Johns Hopkins University and Our World in Data. Many nations have Covid-19 vaccine dashboards where they post regular updates. Where we have gaps or questions about data, our journalists around the world reach out to local health officials to fill them.

For the U.S., we moved to using CDC data for our vaccination tallies beginning Feb. 20. For historic data, we relied on local government websites, press conferences, official social media accounts, and direct correspondence with government officials. Some more recent data, including demographic breakdowns and manufacturer-specific vaccination figures, has been gathered from local sources.

How often do you update the page?

We update vaccination data on a daily basis.

What is your process for data entered by hand?

We wound down our by-hand collection process in August 2021 and moved to using third-party sources, as described here. Prior to that, for our hand-collected data, each data entry has been individually checked by two journalists as it’s entered into our database. Vaccine dashboards are constantly changing, and our priority has been to make sure our data is right. We work to ensure data means what we think it means, that we add new information as it’s posted, and that we transparently correct any errors as soon as we become aware of them.

Do you get new data from every place every day?

Many places update vaccine information every day, or nearly every day. A few locations update weekly, or even every few weeks.

There’s a problem with your data, how do I tell you about it?

We have a form here for all types of feedback.

Why do you use the total population to calculate coverage when children can’t get the vaccine?

Vaccines are being studied in younger populations and will be rolled out for them once proven safe to do so. Also, children are a link in disease transmission and must be included when determining the percentage of a population that needs to be vaccinated in order to slow Covid-19.

Why do you count the number of doses as opposed to the number of people vaccinated?

We count doses because they’re the most commonly reported metric across all countries and regions. While currently approved vaccines require two doses to confer full immunity, each dose is thought to provide some level of protection. We’re constantly adding new data and new ways of looking at vaccination counts.

If a state or country has administered 100 doses, doesn’t that just mean 100 people got vaccinated?

No. The first-approved vaccines require two doses for full vaccination or “series completion.” So 100 doses could, theoretically, mean 50 people with both doses. Or it could mean 100 people who each received one dose each. In practice, there’s a mix of people fully vaccinated and partially vaccinated.

I live in ____. How can I get vaccinated?

Many governments are trying to provide this information through state and local health departments or health ministries. We recommend you look locally for information about vaccination. We don’t currently collect that information.

What do you do when you make mistakes or when data are wrong?

We work to correct data as soon as possible. If you spot something erroneous, please let us know. When we have made corrections to the historic data, we’ll post a note at the bottom of the graphic describing the correction. We also created a methodology and analysis blog to discuss in greater detail the way we do things.

It looks like you changed something. What’s going on?

We have a blog where we talk about methodology and offer some analysis and commentary. That includes things we’re seeing in the data, new data, or if how we present data is changing.

Do you have county-level data or more granular, local data?

We compile state-level data in the U.S. and some limited province-level data outside it.

Why don’t you put greater focus on “people who have received at least one dose,” or “people who have been fully vaccinated?”

Both metrics have drawbacks. Each dose in a two-dose vaccine is thought to confer some amount of protection. Putting too much emphasis on the number of people who have received “at least one dose” downplays the importance of completing the regimen. On the other hand, some countries with limited vaccine supply have considered stretching the time between the first and second doses. We focus first on total doses administered and then include breakdowns of 1st and 2nd doses whenever those data are available.

When will the vaccine let things get back to normal?

It’s a complicated question and the subject of debate among epidemiologists. While the best vaccines are thought to be highly effective, it may still be possible to spread the disease after getting inoculated. Experts have estimated that vaccinating 70% to 85% of the U.S. would enable a return to normalcy, though mutations in the virus may alter that target.

Is your data available for others to use?

Some of our data is available to download on GitHub; see our Terms of Use in the readme document.