Outbreak Guidance
Most cases of illness are isolated to one student, but occasionally an outbreak of a particular disease can occur in a school. The law requires school personnel to report all suspected or confirmed outbreaks to the local public health agency. Guidance and resources for schools and childcare centers including outbreak definitions, when outbreaks are considered over, and action steps required and recommended by public health for the most common outbreaks seen in schools (like Hand Foot Mouth Disease and Influenza) can been seen below. If your school meets the outbreak definition, please report this to our department within 24 hours by following the “Steps” listed under each type of outbreak. Please note schools may implement more restrictive policies, but not less restrictive policies, than the Public Health Department's recommendations.
** If you prefer to report the information by phone, please call our department at 707-565-4568.**
On This Page
Hand, Foot, Mouth Disease (HFMD)
Daycare/School Outbreak Definition
5 or more individuals with HFMD symptoms (skin rash or mouth sores potentially with fever, sore throat, loss of appetite) occurring within a 3 day period AND epidemiologically linked (i.e., within a single classroom, team, or group).
When can the outbreak be considered over?
The incubation period for HFMD is 3-5 days. The outbreak can be considered over 5 days after the most recent case was last at school (e.g. the last day of exposure).
When can students return following exclusion?
Children with HFMD should be kept home from daycare or school until fever free for 24 hours without use of fever reducing medication, sores have healed (scabbed and no longer leaking fluid), and there is no uncontrolled drooling.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using the Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- In addition to following your school’s regular illness and cleaning policies, we recommend the following:
- Wash hands well with soap and water for at least 30 seconds, especially after changing diapers, using the toilet, blowing noses, etc.
- Increased cleaning and deep cleaning/disinfecting of high touch surfaces (desks, chairs, lunch tables) and frequently shared items like toys and doorknobs.
- Restrict sharing of school supplies.
- Cover coughs & sneezes.
- Prevent children from touching their eyes, noses, and mouths with unwashed hands.
- * Consider sending out an exposure notice to parents.
*Also recommended for a single, verified case at a school.
Norovirus/Gastrointestinal Illness
Daycare/School Outbreak Definition
2 or more individuals with Norovirus symptoms (Nausea, Vomiting, and/or Diarrhea) occurring within 1-2 days, with or without laboratory results.
When can the outbreak be considered over?
The average incubation period for norovirus is 2 days. The outbreak can be considered over 4 days (2 incubation periods) after the most recent case was last at school (e.g. the last day of exposure).
When can students return following exclusion?
Sick students and staff should not come to the school or facility until at least 48 hours after resolution of vomiting and diarrhea.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using the Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- Utilize the CDPH Norovirus outbreak packet to control the spread throughout your facility. Important recommendations to emphasize:
- Hand hygiene is ESSENTIAL for everyone – staff and students - at all times. Use soap and water after touching any student or surface area.
- Clean and disinfect frequently touched surfaces and all possibly contaminated areas.
- Refer to “Cleaning and Disinfection Guidelines” section on page 13 and Clean-up and Disinfection for Norovirus (“Stomach Bug”) sheet (Appendix D) for more information.
- Consider cancelling or postponing group activities.
- Consider sending out an exposure notice to parents.
Guidance and Resources
- School Interview Form
- Norovirus/GI Line List – send separate line lists for students and staff
- CDPH School Norovirus Outbreak Packet
- Template Exposure Notice
- Sonoma County Norovirus Fact Sheet
- EPA list of Agents effective against norovirus (if unable to use bleach)
Influenza, Influenza Like Illness (ILI) and other Non-Covid-Respiratory Illesses
Daycare/School Outbreak Definition
At least 10% of average daily attendance is absent with respiratory illness (any two of the following: fever, cough, runny nose, nasal congestion, sore throat, or muscle aches) over a 3-day period facility wide
OR
20% of an epidemiologically linked group (such as a single classroom, sports team, or after-school group) ill with similar respiratory symptoms, with a minimum of 5 ill, sustained over a 3-day period.
When can the outbreak be considered over?
The rate of respiratory illness is down to your school’s “normal”
OR
one week after the most recent case was at school last at school (e.g. the last day of exposure).
When can students return following exclusion?
Children and staff should be fever free for at least 24 hours without use of fever reducing medication before returning. They might have a lingering cough—this is not a reason for exclusion. As long as symptoms are mild and improving, they can return to school. If on antibiotics, children may return 24 hours after starting antibiotic treatment.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using this Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- In addition to following your school’s regular illness and cleaning policies, we recommend the following:
- Frequent and proper handwashing, especially before eating/prepping food and after going to the bathroom, wiping noses, or changing diapers.
- Covering of sneezes and coughs; have tissues available.
- Encourage adequate ventilation of classrooms.
- Prevent sharing of cups and utensils.
- Increase cleaning & disinfection of high touch surfaces and shared objects, such as desks, chairs, doorknobs, and toys.
- Testing for COVID if no other diagnosis has been made.
- Based on severity and feasibility for your school, consider the following:
- Cancelling or postponing group activities.
- Sending out an exposure notice to parents about the increase of respiratory in the classroom.
- Recommending wearing a mask to protect classmates while symptomatic.
Guidance and Resources
- School Interview Form
- Respiratory Line List
- Template Exposure Notices
- What you need to know about COVID-19, flu, common cold, and RSV
- Influenza
- Respiratory syncytial virus (RSV)
- Group A Streptococcus (Strep Throat)
Whooping Cough/Pertussis
Daycare/School Outbreak Definition
2 or more individuals from different households with pertussis symptoms (whooping cough and/or uncontrollable coughing spells potentially with fever, runny nose, sneezing) and/or positive testing occurring within a 3-week period and epidemiologically linked (i.e., within a single classroom, team, or group).
When can the outbreak be considered over?
The incubation period for pertussis is 21 days. The outbreak can be considered over 21 days after the most recent case was last at school (e.g. the last day of exposure).
When can students return following exclusion?
The CDC and the American Academy of Pediatrics recommend school exclusion for children with pertussis until they have completed 5 days of antibiotic treatment.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using the Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- In addition to following your school’s regular illness and cleaning policies, we recommend the following:
- Wash hands well with soap and water for at least 30 seconds, especially after changing diapers, using the toilet, blowing noses, etc.
- Increased cleaning and deep cleaning/disinfecting of high touch surfaces (desks, chairs, lunch tables) and frequently shared items like toys and doorknobs.
- Restrict sharing of school supplies.
- Cover coughs & sneezes.
- Encourage adequate ventilation of classrooms.
- Prevent children from touching their eyes, noses, and mouths with unwashed hands.
- Consider cancelling or postponing group activities.
- * Send out an exposure notice to parents.
- * Instruct high risk** close contacts*** to follow up with their provider asap and within 21 days of last exposure to discuss potential need for PEP (post exposure prophylaxis – medication to prevent illness in those exposed).
*Also recommended for a single, verified case at a school.
** High risk individuals: Infants less than 1 yrs old (especially those less than 4 months (unvaccinated)), pregnant women in their 3rd trimester, and caregivers and household contacts of infants and pregnant women in their 3rd trimester.
*** Close contact: attending or working in the same childcare setting, receiving a cough or sneeze in the face, performing a medical examination of the mouth, nose or throat, sitting at adjacent desks or the same table at school, or sharing a confined space with an infectious person for >1 hour are generally considered significant exposures.
Guidance and Resources
- School Interview Form
- Pertussis Line List - send separate line lists for students and staff
- Template Exposure Notice
- Sonoma County Pertussis Fact Sheet
- CDC Pertussis Website
Chickenpox (Varicella)
Daycare/School Outbreak Definition
3 or more individuals with chickenpox symptoms (itchy rash of small pink bumps all over the body, some of which become round, hard, shiny blisters that will eventually burst, dry and crust over) occurring within a 3-week period and epidemiologically linked (i.e., within a single classroom, team, or group).
When can the outbreak be considered over?
The incubation period for Chickenpox is 21 days. The outbreak can be considered over 21 days after the most recent case was last at school (e.g. the last day of exposure).
When can students and staff return following exclusion?
Once all blisters have crusted/scabbed over and there are no new blisters (usually about 5 days). In the rare case a vaccinated person develops chickenpox, they may develop lesions that don’t blister and crust (macules/ papules only). Such persons should be excluded until no new bumps or blisters appear for 24-hours.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using the Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- In addition to following your school’s regular illness and cleaning policies, we recommend the following:
- Wash hands well with soap and water for at least 30 seconds, especially after changing diapers, using the toilet, blowing noses, etc.
- Increased cleaning and deep cleaning/disinfecting of high touch surfaces (desks, chairs, lunch tables) and frequently shared items like toys and doorknobs.
- Restrict sharing of school supplies.
- Cover coughs & sneezes.
- Prevent children from touching their eyes, noses, and mouths with unwashed hands.
- * Send out an exposure and/or outbreak notice to parents.
- * Instruct exposed** high risk*** individuals to follow up with their provider within 10 days of 1st exposure to discuss potential need for PEP (post exposure prophylaxis – vaccination to prevent illness in those exposed).
- Exclude exposed high risk individuals from an outbreak setting through 21 days after rash onset of the last identified case.
- Because of the high likelihood of infection, it is reasonable to exclude nonimmune siblings for 21 days after the last exposure to the infectious sibling unless symptoms develop.
- If siblings are immune and healthy, they do not need to be excluded from school.
- Healthy, asymptomatic students without evidence of varicella immunity don’t need to be excluded from school during an outbreak.
*Also recommended for a single, verified case at a school. If no testing has been done, at least an MD diagnosis is recommended.
**Exposure involves close contact with an infectious person, such as direct physical or face-to-face contact, or one or more hours of indoor contact (e.g. in the same room). Exposure does not include transitory contact.
*** High risk individuals are those at increased risk for complications from varicella disease because of their age or an underlying condition and include pregnant staff and immunocompromised (weakened immune system) persons
Guidance and Resources
- School Interview Form
- Chickenpox (Varicella) Line List - send separate line lists for students and staff
- Template Exposure Notice
- Sonoma County Chickenpox (Varicella) Fact Sheet
- CDC Chickenpox (Varicella) Website
Measles
Daycare/School Outbreak Definition
2 or more epidemiologically-linked (i.e., within a single classroom, team, or group) cases of measles where at least one is laboratory confirmed and occurring within 42 days of each other.
When can the outbreak be considered over?
The incubation period for measles is 21 days. The outbreak can be considered over 42 days (2 incubation periods) after the last confirmed case is reported (42 days after rash onset in last case).
When can students and staff return following exclusion?
On the fifth day after rash onset, if not immunocompromised.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using the Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- In addition to following your school’s regular illness and cleaning policies, we recommend the following:
- Wash hands well with soap and water for at least 30 seconds, especially after changing diapers, using the toilet, blowing noses, etc.
- Increased cleaning and deep cleaning/disinfecting of high touch surfaces (desks, chairs, lunch tables) and frequently shared items like toys and doorknobs.
- Restrict sharing of school supplies.
- Cover coughs & sneezes.
- Encourage adequate ventilation of classrooms.
- Prevent children from touching their eyes, noses, and mouths with unwashed hands.
- Consider cancelling or postponing group activities.
- * Send out an exposure notice to parents.
- * Instruct close contacts to follow up with their providers for PEP (post exposure prophylaxis – vaccination to prevent illness in those exposed) immediately, but ideally within 72 hours after exposure. The public health department will assist with identifying who is a close contact and informing them.
- Exclude persons who continue to be exempted from or who refuse measles vaccination until the outbreak is determined over.
- Persons receiving their second dose of MMR and previously unvaccinated persons receiving their first dose of MMR appropriately (i.e., before, or within 72 hours of, exposure) can be immediately readmitted to school. However, these individuals should be monitored for signs and symptoms of measles.
*Also recommended for a single, verified case at a school.
Guidance and Resources
- School Interview Form
- Measles Line List - send separate line lists for students and staff
- Template Exposure Notice
- Sonoma County Measles Fact Sheet
- CDC Measles Website
Meningococcal
Daycare/School Outbreak Definition
Multiple confirmed or probable primary cases of meningococcal disease occurring over a short period of time. This may be as little as 2 cases depending on the size of the school. The health department will help schools determine if there is an ongoing outbreak.
When can the outbreak be considered over?
The incubation period for Meningococcal is 10 days. The outbreak can be considered over 10 days after the most recent case was last at school (e.g. the last day of exposure).
When can students and staff return following exclusion?
24 hours after the initiation of appropriate antibiotic therapy.
Steps
- Fill out the School Interview Form with information about your school and the outbreak. Fax (707-565-4565) or email (phnurse@sonoma-county.org) to Sonoma County Disease Control.
- Start completing line lists using the Line List Template. Fax (707-565-4565) or email (phnurse@sonoma-county.org) at the start of the outbreak and if/when there are new cases.
- In addition to following your school’s regular illness and cleaning policies, we recommend the following:
- Wash hands well with soap and water for at least 30 seconds, especially after changing diapers, using the toilet, blowing noses, etc.
- Increased cleaning and deep cleaning/disinfecting of high touch surfaces (desks, chairs, lunch tables) and frequently shared items like toys and doorknobs.
- Restrict sharing of school supplies.
- Cover coughs & sneezes.
- Encourage adequate ventilation of classrooms.
- Prevent children from touching their eyes, noses, and mouths with unwashed hands.
- Consider cancelling or postponing group activities.
- * Send out an exposure notice to parents.
- * Instruct close contacts to follow up with their providers for PEP (post exposure prophylaxis – medication to prevent illness in those exposed), ideally within 24 hours of identification of the index case and up to 14 days from the last exposure. The public health department will assist with identifying who is a close contact and informing them.
*Also recommended for a single, verified case at a school.
Guidance and Resources
- School Interview Form
- Meningococcal Line List - send separate line lists for students and staff
- Template Exposure Notice
- Sonoma County Meningococcal Fact Sheet
- CDC Meningococcal Website