Three and six days (±1 day) after the initial home visit, a trained nurse will revisit each household. During the visit, the nurse will take nose swabs and throat swabs from the index case and all household contacts, except for children under 2 years of age who are asymptomatic, and collect the symptom diaries (questionnaire Q3, appendix) from each household contact. During the final visit (day 6), the nurse will ask the household members to complete a final questionnaire (Q4, appendix) and assess their adherence to the interventions (questionnaire Q5, appendix).