The aim of this study is to investigate the feasibility of continuous fever tracking of participants having fever symptoms in a home setting, using a core body temperature (CBT) sensor. CBT as measured by the wearable sensors will be coampared with CBT as measured by ingestible electronc pills (reference).

A secondary research question is, if the CBT behavior of the the participants in a home setting can be compared to previously described CBT profiles in the literature, and if special patterns can be identified.

Inclusion Criteria:

• Age 18-60 years old
• Informed consent signed
• Either:

Acute fever symptoms at inclusion (at least 38.0°C) and Test for COVID-19 at the day of inclusion

- Or: Second shot or booster of mRNA COVD-19 vaccination (Comirnaty® or COVID-19 Vaccine Moderna®) at day of inclusion

Exclusion Criteria:

• Any participant who, for any reason, is unable to independently consent to participate in the study and/or who is unable to independently follow the study protocol.

• Any participant with previous surgical procedures in the gastrointestinal tract

• Inability to swallow pills

• Any participant of ≤40 kg body weight

• A scheduled MRI examination in the period from the start of the measurements until seven days after ingestion of the electronic pill.

• Any participant being pregnant

• Impairment or disability of the upper extremity likely to have a negative impact on the quality of measurements:

  • Wounds
  • Active venous access
  • Amputations
  • Dialysis shunt
  • Edema
  • Axillary dissection
  • Continuous long-term monitoring of blood pressure
  • Tattoos

• Known allergy to plastics / latex

• Language problems

Subjects testing for COVID-19 at the University Hospital Basel and having acute fever symptoms, or individuals receiving the second shot or the booster of an mRNA COVID 19 vaccination, will be informed about the possibility to participate in this study by study personnel on-site.