Flu and Seasonal Influenza Vaccine

Section 1.1

Midwives may independently prescribe, order and administer this drug.

Flu and seasonal vaccines are reformulated annually because the influenza viruses change in ways that make a previous year’s vaccine ineffective. Included are standardized amounts of the Hemaglutin (HA) protein from representative seed strains of the two human influenza A subtypes (H3N2 and H1N1) and one of the two influenza B lineages.

Indications and Clinical Use:

Due to the increased severity of influenza in pregnancy, inactivated influenza vaccine is recommended during pregnancy regardless of trimester of pregnancy. Immunization during pregnancy has the advantage of potentially protecting the fetus through transplacental antibody passage or through breast milk. Among healthy pregnancies, the morbidity and mortality associated with influenza is increased during pandemics.

If healthy and pregnancy is planned to occur during influenza season, vaccination during any trimester of pregnancy can occur to avoid morbidity associated with influenza. If delivery is expected during influenza season, immunization can occur in the third trimester to reduce the risk of infection of the newborn.


Known allergy to any vaccine component; or previous severe reactions and/or allergic reactions following the administration of a flu vaccine such as difficulty breathing, tightness in the chest, tachycardia, wheezing, hives, confusion, hallucinations.

Warnings and Precautions:

Influenza vaccine is considered safe at all stages of pregnancy and during breastfeeding. Chronic conditions during pregnancy are a predisposition to high risk complications associated with influenza and these pregnancies are a priority for immunization.

* Live vaccines administered during pregnancy may cause risk to the fetus; live, attenuated virus and live bacterial vaccines are generally contraindicated during pregnancy.


Compatible – inactivated influenza vaccines can be used during all stages of pregnancy


Category L1 – Limited Data – Compatible

Adverse Reactions:

Possible reactions are usually mild and temporary and my include tenderness, redness, itching, bruising, and muscle ache at injection site; or headaches, fatigue, fever and myalgias.

Dosage and Administration:

Seasonal Influenza vaccine – Influenza vaccines in Canada are available as a split-virus (chemically disrupted) and an inactivated subunit preparation. Each 0.5 mL of vaccine dose contains 15 mcg of influenza hemagglutinin (HA) of each of the three virus strains (two type A strains and one B strain).

0.5 mL dose of the inactivated subunit preparation administered IM. The deltoid muscle is the recommended site in adults.