Registration of vaccinated

A number of questions have been submitted to SIR regarding our registration of vaccinations and differences reported between our data and data presented from (Public Health Agency of Sweden) Fohm.

The difference is because SIR and Fohm have used different definitions in the presented data. What SIR records and presents is whether a vaccination is given or not. SIR has registered unknown in situations where the available data is not available at the time of registration.

The Public Health Agency of Sweden has published the report:
Protective effect of vaccination against COVID-19 in age groups 65 years and older.

The definition used in the report is:

  • Unvaccinated (up to dose one +21 days)
  • Vaccinated at dose one +21 days or more (until dose two +14 days)
  • Vaccinated at dose two +14 days or more

Fohm also analyzes vaccination breakthroughs and the effect of the vaccination program against Covid-19. Fohm then uses the National Vaccination Register where full information is available including the date of the respective dose. In the analysis, Fohm uses a specific definition for breakthrough infections based on when people are expected to have received full protection.

The definition used by Fohm in the production of statistics on breakthrough infections is:

  • Unvaccinated – people who were not vaccinated before falling ill or being tested for COVID-19.
  • Breakthrough infections – people who have been vaccinated with two doses of vaccine, and it was then at least two weeks before the person fell ill or was sampled.

SIR has had a discussion with Fohm about SIR switching to Fohm's definition of "vaccination status" but decided that SIR retains the definition used by SIR when SIR started recording vaccinated. There are several arguments as to why we have chosen this line.

  1. Fohm does not believe that Fohm and SIR must have the same definition.
  2. It may be better to continue with existing data collection, and leave it the same during the pandemic.
  3. It is easiest to find data regarding the given syringe or not.
  4. Time between vaccination and onset date need not be calculated.

Finally, however, it is important (as always) to point out that data can be reported in different ways and knowledge of the background is important.