Do family members of a person with influenza need to quarantine also?

Family Members of Influenza Patients Do Not Need Routine Quarantine

Family members of a person with influenza do not need to quarantine in routine circumstances. Instead, the focus should be on vaccination of household contacts, voluntary home isolation of the sick person, and consideration of antiviral prophylaxis for high-risk household members 1.

Key Recommendations for Household Management

The Sick Person Should Isolate, Not the Entire Household

• The person with influenza should remain at home for approximately 7 days to reduce contacts outside the household by 75%, but other household members can continue normal activities if they are well 2, 1.
• Patients with influenza are contagious starting 1 day before symptoms develop and typically remain infectious for approximately 5 days after symptom onset 1.
• The European Centre for Disease Prevention and Control recommends early isolation at home of people feeling unwell and feverish when influenza is circulating, but quarantine is not generally recommended for routine influenza cases due to practical challenges and the rarity of pre-symptomatic transmission 1.

Voluntary Home Quarantine: Only in Specific Circumstances

• Voluntary home quarantine of the entire household is only recommended if a symptomatic case is identified AND there are high-risk individuals in the home 2.
• If implemented, the entire household should remain at home for 14 days, which decreases contacts outside the household by 75% but increases household contact two-fold 2.
• This measure is not standard practice for routine influenza cases in otherwise healthy households 1.

What Family Members Should Do Instead

Vaccination is the Priority

• All household members (including children) of high-risk persons should be vaccinated against influenza 2.
• Household members should be up-to-date with all routinely recommended vaccinations including annual influenza vaccine 2.
• Vaccination of household contacts creates a "circle of protection" around vulnerable individuals 2.

Antiviral Prophylaxis for High-Risk Contacts

• Antiviral prophylaxis should be considered for household contacts who are at high risk of complications if exposed to a confirmed influenza case 2.
• Oseltamivir or baloxavir are conditionally recommended for prophylaxis in asymptomatic persons who have been exposed to seasonal influenza and would be at very high risk of hospitalization 3.
• In post-exposure prophylaxis trials, oseltamivir 75 mg once daily for 7-10 days reduced the incidence of laboratory-confirmed influenza in household contacts from 12-19% to 1-4% 4, 5.
• Zanamivir 10 mg inhaled once daily for 10 days reduced household transmission from 19% to 4% in clinical trials 4.

Basic Infection Control Measures

• Regular handwashing and good respiratory hygiene (covering mouth and nose when coughing or sneezing) are strongly supported as key components of personal protective measures 1.
• Avoid contaminating environmental surfaces such as door handles 2.
• If possible, use disposable or dedicated equipment (thermometers, etc.) for the sick person 2.

Special Circumstances Requiring Stricter Measures

Institutional Outbreaks

• Nursing homes, hospitals, and other institutional settings require more stringent control measures including isolation of confirmed or suspected cases, droplet precautions, and establishing cohorts of patients 1.
• During institutional outbreaks, chemoprophylaxis should be administered to all residents regardless of vaccination status 1.
• Healthcare workers should wear appropriate personal protective equipment including surgical masks, gloves, and gowns when caring for influenza patients 1.

Immunocompromised Household Members

• If the household includes severely immunocompromised persons (such as recent transplant recipients or those with severe combined immunodeficiency), more aggressive measures may be warranted 2.
• Household members of severely immunocompromised patients should receive inactivated influenza vaccine (not live attenuated vaccine) 2.

Common Pitfalls to Avoid

• Do not confuse influenza with COVID-19 protocols: The quarantine recommendations for COVID-19 are much more stringent due to significant pre-symptomatic and asymptomatic transmission, which is rare with influenza 1, 6.
• Do not delay antiviral prophylaxis: If considering prophylaxis for high-risk contacts, it must be started within 48 hours of exposure to be effective 2, 5.
• Do not rely on quarantine alone: Mathematical models show that household quarantine has minimal impact on transmission unless combined with other measures like antiviral prophylaxis and case isolation 7, 8.