Influenza
/What is flu, and why do we care about it in pregnancy?
We reviewed the flu vaccine in pregnancy previously, but we have never talked specifically about flu itself!
Flu is a contagious respiratory illness caused by the influenza virus
The virus is a negative sense RNA virus
There are multiple strains, including A, B, C, D
We have probably heard about A and B, but C and D also can infect people
A and B are known to cause more severe illness, while C can cause can cause a mild infection
D can infect humans, but is not known to cause illness
Transmission is through aerosols and contaminated surfaces
Why do we care about flu so much?
In typical years, as much as 5-15% of the population will contract flu
This leads to 3-5 million severe cases annually and up to 650,000 flu deaths a year in the world
In the US, on average, 8% of the population gets sick from the flu, per the CDC
Who is most likely to get sick?
Children are most likely to get sick from flu and people 65 and older are least likely to get sick
However, pregnant and postpartum individuals are at significantly higher risk of serious complications related to seasonal and pandemic influenza infections compared to non pregnant people
How is flu prevented?
Vaccination
The CDC recommends that all adults receive an annual influenza vaccine and that individuals who are pregnant during the season receive an inactivated or recombinant influenza vaccine as soon as possible
Timing: end of October is ideal, but any time during flu season vaccination should be encouraged
Remember that it is safe to give the flu vaccine with other inactivated vaccines that may be needed in pregnancy (ie. Tdap, RSV, or COVID vaccines)
It is also safe for lactating individuals to receive the flu vaccine
Of note, the vaccine also benefits the newborn when it is given during pregnancy
Randomized controlled trials and observational studies have shown neonatal protection from maternal influenza vaccination
Importantly, studies show that when recommendations for the flue vaccine during pregnancy come from the patient’s Ob/Gyn or other obstetric health professional, and the vaccine was available in the office, the odds of vaccine acceptance and receipt are 5x-50x higher!
For more information on the flu vaccine, check out our previous episode: https://creogsovercoffee.com/notes/2019/5/26/vaccines-i-tdap-and-influenza
Masks
This is probably familiar to all of us now with the COVID-19 pandemic
Mask wearing can help prevent transmission of many respiratory infections, particularly when community levels of circulating viruses are elevated
When to wear a mask
Local public health guidance and recommendations based on community-centered risks
Individual’s specific vulnerability due to health conditions
Clinical and health care professional recommendations
Other methods
Hand washing
Cleaning surfaces regularly
Make sure to to use usual techniques to minimize contamination/spread of disease
How should we evaluate for influenza in pregnancy?
Assess for symptoms
Fever >100.4 F (38 C) and one of the following
Cough, runny nose, sore throat, headache or body aches, fatigue, difficulty breathing or SOB
If these symptoms are present, test for COVID and flu
Also assess for illness severity
Difficulty breathing or shortness of breath
Chest pain/pressure
Unable to keep down liquids
Dehydration signs and symptoms
Less responsive, confused
Symptoms are worsening
If yes to any of the above, then encourage patient to go to emergency room or equivalent location to be treated
If no, if there are other morbidities (ie. cardiovascular or pulmonary issues, immunosuppression, obstetric issues like preterm labor) → should be seen in a clinical setting as moderate risk
Otherwise, patient is considered low risk and patient can be treated outpatient or even over the phone, with follow up in 24-48 hours
How to Treat Respiratory Infection in Pregnancy
Empiric treatment
Oseltamivir is the preferred treatment for pregnant individuals
Dosing: 75 mg orally twice a day for 5 days
Zanamivir can also be used (two 5 mg inhalations twice daily for 5 days)
Peramivir can also be given, but is 1 dose IV for 15-30 min
Do not delay treatment while respiratory infection test is running
If suspected to have both COVID and flu, oseltamivir and Paxlovid can be prescribed and taken together
Post Exposure chemoprophylaxis for flu
Due to high potential for morbidity and mortality related to flu in pregnant and postpartum individuals, post exposure chemoprophylaxis can be considered for those who are pregnant and for those who are up to 2 weeks postpartum
Recommendation: oseltamivir 75 mg 1x/day for 7 days
Should be started within 48 hours of most recent exposure
At risk family members of patients with flu should be referred to health care professionals for consideration of chemoprophylaxis