You asked
Please provide the following information:
If someone does a COVID-19 test and they test positive for antibodies meaning not currently infected but were infected in the past is this considered a positive case?
If you test positive go into quarantine and have a retest after 2 or 3 weeks is this considered a second positive case?
If someone does 5 x COVID-19 tests in 1 month and they come back positive is this considered as 5 positive cases ?
Can 1 person account for multiple positive cases ?
Can 1 persons retesting be responsible for multiple positive cases ?
We said
Thank you for your request.
In our study, to find out how many people have COVID-19 now, we test for the virus using self-administered nose and throat swabs at each study visit (parents/carers will be asked to take the swab from children aged 2-11 years). This is used to calculate the positivity rate i.e. the percentage of people testing positive for COVID-19.
This differs from antibody testing which is used to find out how many people have had COVID-19 in the past. In a subset of the households visited, optional consent will also be sought for adults aged 16 years or older to have a blood draw for antibody testing. Results from antibody testing are not used to calculate the positivity rate and are instead published separately. Please see our latest article for the latest antibody results.
Everyone that tests positive for COVID-19 at the point of test are included in the number of people testing positive. We do not report a running total of the positive cases, rather we report the number of people who have the virus during a certain period of time, so it possible for individuals to feature in multiple periods.
We calculate incidence (the number of new infections in a set period of time) by directly measuring when a participant in the study who has previously tested negative subsequently tests positive and comparing this with the number of participants who remain negative. Therefore, only the first positive is included in the incidence calculation and you would be included in the incidence rate multiple times only if you tested negative in the middle.
Please note this information is from the COVID-19 Infection Survey; a representative household survey which estimates the number of people testing positive for COVID-19.
Public Health England (PHE) presents data on the total number of laboratory-confirmed cases in the UK, which capture the cumulative number of people in the UK who have tested positive for COVID-19. Further information can be found on the Coronavirus Dashboard.