Fever after a family member gets COVID-19: how do you tell the doctor about contact at home?

Hello. I am Shunichi Gamo, MD, PhD, a board-certified pulmonologist and the director of Sendai International Airport North Clinic.

A few days after someone you live with is diagnosed with COVID-19, you or your child may also get a fever. You may wonder, “Did I catch it after all?” You may also wonder, “How much should I say about my family when I see the doctor?” These are natural questions. When you are sick with a fever, it is hard to plan what to say and in what order.

This article explains how to think about your own fever when a family member has COVID-19. It also covers how to describe contact at home when you see a doctor, the signs that mean you should get care quickly, and how long to stay home.

日本語

If a family member has COVID-19, can I assume my fever means I caught it?

If you get a fever after a family member has had COVID-19, you may have caught it. But a fever alone cannot tell you the cause, and you cannot know whether it is COVID-19 until you are tested. Colds, flu and other infections besides COVID-19 also cause fever. Until the cause of your fever is confirmed, do not simply follow the advice meant for people diagnosed with COVID-19. Instead, get tested and see a doctor to find out.

One study from early in the pandemic looked at 930 people who visited a fever clinic in Germany in April and May 2020 (74 of them had COVID-19). People who had contact with someone in the same household, and people with more household members who had cold-like symptoms, were more likely to have COVID-19. [1] Separately, a loss of the sense of smell or taste was also strongly linked to COVID-19. [1]

The current situation and the variants going around are different from back then, so you do not need to take the study’s numbers as your own chances. Still, the fact that a family member tested positive is an important clue to tell the doctor when you are seen.

How should I describe contact with a family member who has COVID-19 when I see a doctor?

You can describe contact at home briefly but clearly by focusing on three points: “who,” “since when” and “how much time you spent together.” The key is to talk about your family member’s condition and your own condition separately.

What to tell the doctor	Details to give
Your family member’s diagnosis	Who tested positive, when, and where they were tested. Also say if it is only suspected based on symptoms
When your family member got sick	The day that family member first had symptoms
How close the contact was	Whether you sleep in the same room, ate meals together, were the one caring for them, or used separate rooms
When you got sick	The date and time your fever started, and the highest temperature you measured
Your own test	Whether you tested at home, and if so, when and what the result was
Other family members	Whether anyone else at home is also feeling unwell

Please also tell the doctor how other family members are feeling. Whether anyone else in the same home is sick helps the doctor understand the situation. For example, you could say: “My husband, who lives with me, was diagnosed with COVID-19 three days ago, and I have had a fever of 38.5°C since last night. We share a bedroom, and I was the one looking after him.”

If you are not sure of the dates, just say what you can. For example: “I think it was two or three days after my family member’s fever started.” If you write the items in the table above in a note on your smartphone before your visit, you can talk calmly in the exam room.

When a family member has COVID-19, which symptoms besides fever should I mention to help the diagnosis?

If you have a fever while a family member has COVID-19, be sure to mention, along with the fever, whether you have lost your sense of smell or taste. In a study at a fever clinic in Germany in 2020, problems with smell and taste were especially strongly linked to COVID-19. [1] However, a normal sense of smell and taste does not mean you do not have COVID-19. It is important not to base the diagnosis on a combination of symptoms alone.

There is a 2020 review article (a paper that summarizes the research so far). It lists fever, cough, sore throat, headache, tiredness, muscle aches and shortness of breath as symptoms of COVID-19, and notes that illness ranges from no symptoms at all to pneumonia. [2] You do not need to search hard for symptoms you do not have.

Symptom	How you might say it	Link to the diagnosis
Changes in smell or taste	“I haven’t been able to taste my food since yesterday.”	In a study of 930 people who visited a fever clinic in Germany, this symptom was especially strongly linked to COVID-19. [1]
Cough, sore throat	“My cough is dry, and it gets worse at night.”	The review lists these as common symptoms of COVID-19. [2]
Shortness of breath	“I get out of breath on the stairs.”	One of the symptoms listed in the review. [2] Shortness of breath is also a sign to get care quickly.
Headache, tiredness, muscle aches	“My whole body feels so tired that I can’t get up.”	The review lists these symptoms alongside fever. [2]

Make a note of only the symptoms you actually have, with “since when” and “how bad.” This makes them easier to explain during your visit.

If a family member tests positive for COVID-19, is my fever confirmed as COVID-19?

Even if a family member tests positive for COVID-19, the cause of your fever is not confirmed until you are tested. Your contact history and symptoms are only clues to the diagnosis. The authors of the German fever clinic study also say that contact information is useful for deciding on infection control while waiting for test results. They add that it does not replace testing, such as a PCR test (a test that copies the virus’s genes many times so they can be detected). [1]

In a 2020 report on 74 children, almost all of them had been in contact with adult family members. [3] On the other hand, 34 of the children were tested for other germs (viruses or bacteria that cause illness) that infect the airways. In about half of them, a germ other than the COVID-19 virus was also found. [3] These results are from children, but they show that other germs can sometimes be found together with the COVID-19 virus.

If you used a home antigen test (a quick test that looks for parts of the virus), tell the doctor when you tested and what the result was, whether it was positive or negative.

Separating what is confirmed from what is not yet known makes the situation easier for the doctor to understand. For example: “My family member tested positive. I have a fever, and I haven’t been tested yet.”

If my child gets a fever after catching COVID-19 from a family member, what should I tell the doctor?

If your child gets a fever after a family member has had COVID-19, first tell the doctor your child’s age and whether your child is able to drink and eat.

In a study of 10,021 children aged 0 to 14 who were confirmed positive for COVID-19 at pediatric clinics in Spain (May 2020 to April 2021), 43.2% of the children had no symptoms. [4] Eighteen were admitted to the hospital, and none died. [4]

In a study of 300 infants diagnosed between March and December 2020 and entered in a database shared by several hospitals, 31.3% had digestive symptoms. [5] In infants, poor appetite can lead to a hospital stay, and the authors list changes in an infant’s feeding as a reason to consider testing for COVID-19. [5]

These are studies from other countries, with data from the strains going around at the time. They may not apply directly to children in families in Japan. For a young child, it helps if you can give a number, such as roughly what percentage of their usual amount of breast milk, formula or fluids they are drinking.

If a family member has COVID-19 and I get a fever, when should I get care quickly?

Even when you get a fever after a family member has COVID-19, the signs that call for quick care are the same. If you have trouble breathing or are breathing fast, seek medical care right away, even at night or on a holiday. If you cannot drink fluids, or an infant will hardly take any formula or breast milk, seek medical care even at night or on a holiday. If the person who is ill has pale lips or a pale face, seems dazed and slow to respond when spoken to, is limp, or has had a seizure, call 119.

A study of infants reports that pneumonia can lower oxygen saturation (the oxygen level in the blood, shown as a percentage and measured with a device on the fingertip). [5] Cases needing oxygen treatment have also been reported. [5] Even if a family member has COVID-19, what decides whether you need care quickly is not their diagnosis but how you are doing right now.

A 2020 review lists people at higher risk of severe illness (the disease becoming serious). They include older people, people with a weakened immune system, and people with ongoing conditions such as high blood pressure, diabetes, cancer, lung disease, or heart and blood vessel disease. [2] In its guidance on how long to stay home, Japan’s Ministry of Health, Labour and Welfare (MHLW) also asks people to talk to a doctor if their symptoms are severe.

How you are now	What to do
Short of breath, breathing fast, or it is harder to breathe when lying down	Seek medical care right away, even at night or on a holiday
Lips or face look pale, slow to respond when called, limp, or has had a seizure	Call 119 (Japan’s emergency number for an ambulance)
Can hardly drink any fluids, or an infant will hardly take any formula or breast milk	Seek medical care even at night or on a holiday
Has a fever but can drink, breathing is easy, and does not seem limp	See a doctor during regular clinic hours and mention your family member’s diagnosis
Older age, an ongoing medical condition, or pregnancy	Call for advice soon, even if symptoms are mild

If you are unsure, calling for advice about being seen can put your mind at ease. Mention your family member’s diagnosis and your own symptoms.

If a family member has COVID-19 and I get a fever, how long should I avoid going out or going to school?

While you have a fever and COVID-19 has not yet been confirmed, avoid going out except to see a doctor until testing and a medical visit show the cause. If you find out you have COVID-19, the general guideline is to stay home for 5 days, counting the day your symptoms started as day 0. On May 8, 2023, COVID-19 became a Class 5 infectious disease (one of the categories set by Japan’s Infectious Diseases Control Law). Since then, neither infected people nor the family members they live with are required by law to stay home. The MHLW says that whether to stay home is a personal decision. That said, it recommends staying home for 5 days.

If you still have symptoms on day 5, the MHLW also recommends that you keep staying home and watch how you feel. It recommends doing this until about 24 hours have passed since your fever has gone down and symptoms such as phlegm and sore throat have gotten better.

For household members who do not have symptoms yet, the MHLW advises them to watch their own health closely, especially for 5 days. Day 0 is the day the infected family member’s symptoms started. It notes that they may get sick up to day 7. When a family member is infected, the MHLW also recommends using separate rooms if possible and having as few people as possible look after them.

The same guidance says that infected people shed infectious virus from 2 days before symptoms start until 7 to 10 days after. It warns that the risk of passing the virus to others is especially high for the first 5 days after symptoms start.

For school children, there are rules under the Enforcement Regulations of Japan’s School Health and Safety Act. For COVID-19, a child must stay home from school “until 5 days have passed since symptoms started, and 1 day has passed since symptoms improved.” This is the standard for going to school, and it is separate from the general advice for adults about staying home. It cannot be applied as is to a child who has a fever but has not yet been diagnosed with COVID-19. Keep your child home from school while they have a fever, see a doctor to find out the cause, and then talk with the doctor and the school. How much time to take off work depends on your employer’s rules. Tell your workplace the date of your family member’s diagnosis and the date your fever started, and ask what to do.

Who	Guideline	Source
A person found to have COVID-19	Stay home for 5 days, counting the day symptoms started as day 0. If symptoms continue on day 5, watch how you feel until about 24 hours after symptoms get better	MHLW
Family members living together (if you do not have symptoms yet)	No legal requirement to stay home. Watch your health closely, especially for 5 days, counting the day the infected family member’s symptoms started as day 0. You may get sick up to day 7. If you already have a fever, follow the advice above	MHLW
School children (if diagnosed with COVID-19)	Stay home from school until 5 days have passed since symptoms started and 1 day has passed since symptoms improved	Enforcement Regulations of the School Health and Safety Act

If you also test positive, write the day your symptoms started on a calendar so you can count the days.

Summary

• If someone you live with has COVID-19, first suspect that you may have caught it, but a fever alone cannot tell you for sure. Only testing can confirm it.
• Give dates for your family member’s diagnosis and when they got sick, the day your fever started, and how close your contact was.
• Saying whether you have any change in smell or taste gives the doctor more clues for the diagnosis.
• If you have signs such as shortness of breath or being unable to drink fluids, seek medical care even at night, whatever your family member’s diagnosis. If the person who is ill is slow to respond or has had a seizure, call 119.
• If you have COVID-19, stay home for 5 days, counting the day symptoms started as day 0. Children must stay home from school until 5 days after symptoms started and 1 day after symptoms improved.

Frequently asked questions

If a family member has COVID-19 and I also get a fever, is it definitely COVID-19?

Not necessarily. Infection in someone you live with is a big clue, but only testing can confirm it. In a study of children, about half of the 34 children tested for respiratory germs also had a germ other than the COVID-19 virus detected at the same time. [3] Tell the doctor the date of your family member’s diagnosis and the day you got sick, and then get tested.

How many days after my family member got sick can I assume I won’t catch it?

There is no day when you can say for sure that you won’t catch it. The MHLW says that an infected family member sheds infectious virus from 2 days before symptoms start until 7 to 10 days after. It also says the risk of passing it to others is especially high for the first 5 days after symptoms start. The same guidance says you may get sick up to day 7, counting the day your family member’s symptoms started as day 0. If you get a fever after day 7, please still see a doctor for advice. While your family member has symptoms, keep taking steps such as using separate rooms and limiting who looks after them.

My home test kit was negative. Should I still tell the doctor about my family member?

Yes, please do. Along with the test result, contact at home is important information for the doctor’s assessment. Share the date, time and result of your test, and the date of your family member’s diagnosis, exactly as they are. Then the doctor can decide when to retest and also consider whether you might have a different illness.

My family member has COVID-19, but I only have a fever and otherwise feel fine. Do I need to see a doctor?

If you are not short of breath, can drink fluids and do not seem limp, it is fine to see a doctor during regular clinic hours. However, older people and people with ongoing medical conditions are considered to be at higher risk of severe illness. [2] If this applies to you, get advice soon, even if your symptoms are mild. When you are seen, mention the date of your family member’s diagnosis and the day you got sick.

Disclaimer

This article provides general medical information. It does not replace an examination, diagnosis or treatment by a doctor. The content is based on medical knowledge at the time of publication, but the right approach differs with each patient’s condition and background.

If you are worried about your symptoms, please talk to your regular doctor or a specialist medical facility.

References

1. Trübner F, Steigert L, Echterdiek F, Jung N, Schmidt-Hellerau K, Zoller WG, et al. “Predictors of COVID-19 in an outpatient fever clinic.” PLoS One, 2021; 16(7): e0254990. DOI: 10.1371/journal.pone.0254990 PMID: 34288955
2. Deshmukh V, Tripathi SC, Pandey A, Deshmukh V, Vykoukal J, Patil A, et al. “COVID-19: a conundrum to decipher.” Eur Rev Med Pharmacol Sci, 2020 May; 24(10): 5830-5841. DOI: 10.26355/eurrev_202005_21378 PMID: 32495923
3. Wu Q, Xing Y, Shi L, Li W, Gao Y, Pan S, et al. “Coinfection and Other Clinical Characteristics of COVID-19 in Children.” Pediatrics, 2020 Jul; 146(1): e20200961. DOI: 10.1542/peds.2020-0961 PMID: 32376725
4. Carballal-Mariño M, Balaguer-Martínez JV, García-Vera C, Morillo-Gutierrez B, Domínguez-Aurrecoechea B, Jimenez-Alés R, et al. “COVID-19 clinical features in primary care: COVIDPAP study.” An Pediatr (Engl Ed), 2022 Jul; 97(1): 48-58. DOI: 10.1016/j.anpede.2022.06.004 PMID: 35725821
5. Sobolewska-Pilarczyk M, Pokorska-Śpiewak M, Stachowiak A, Marczyńska M, Talarek E, Ołdakowska A, et al. “COVID-19 infections in infants.” Sci Rep, 2022 May 11; 12(1): 7765. DOI: 10.1038/s41598-022-11068-0 PMID: 35546159