Coronavirus FAQs: What constitutes a fever and other 'hot' questions answered

Patients at the Toa Payoh Polyclinic on Jan 14, 2020.
Patients at the Toa Payoh Polyclinic on Jan 14, 2020.ST PHOTO: KUA CHEE SIONG

SINGAPORE - With the ongoing coronavirus situation and fever being one of the symptoms of infection, what actually constitutes a fever - and does it differ between babies and adults?

The Straits Times answers some commonly asked questions with input from Dr Edwin Chng, medical director at Parkway Shenton, and public healthcare cluster National Healthcare Group (NHG). Information taken from NHG's website regarding fever was not developed to include information specific to the coronavirus.

Q: At what temperature does a person have a fever, and does it differ for children and adults? Does it matter which part of the body the temperature is taken from?

A: The temperature elevation that is considered "abnormal" depends on the age of the child and the site where the temperature is measured.

In an otherwise healthy neonate - defined as a newborn or a baby up to 30 days of age - and a young infant - aged one to three months - a fever of concern generally is defined by a temperature in the rectum of 38 deg C or higher.

In children aged three to 36 months, fever generally is defined by rectal temperature ranging from 38 to 39 deg C. If there is no focus of infection when the child is examined, a fever of concern would be one in which the rectal temperature is 39 deg C or higher.

For older children and adults, a fever may be defined by oral temperatures ranging from 37.8 to 39.4 deg C, while a fever of concern would be one in which an oral temperature is 39.5 deg C or higher.

The temperature under the armpit, also called axillary temperature, is considered to be abnormal when it is above 37.5 deg C.

Q: What makes a person's temperature fluctuate?

A: Dr Chng said that normal body temperature varies with age, time of the day, level of activity, and, for older girls and women, the phase of the menstrual cycle, among other factors.

Q: Why are children more at risk?


A: NHG said on its website that children tend to have fever more often than adults due to their weaker immune system. It said common causes of fever in children are infections, overdressing by wearing clothes that are too thick, teething or vaccination.

Q: How can I avoid getting a fever?

A: NHG's website says illnesses that cause fever can be prevented by stopping the spread of germs.

These include washing hands often with soap and water, practising proper hygiene which involves washing hands before touching food, or covering your mouth and nose when sneezing and coughing.

A healthy diet including fruits and vegetables, and getting enough sleep can also help prevent illnesses that cause fevers.