Flu virus infection is a common cause of acute respiratory illness, with a significant pediatric age incidence, high morbidity, and mortality. The flu vaccine is recommended for all people aged greater than equal to six months unless specific contraindications are present. Older and younger age, chronic diseases like asthma, immunodeficiency, and pregnancy are risk factors for severe flu infection complications. Live‐attenuated influenza virus (LAIV), recombinant influenza vaccine (RIV), or inactivated influenza vaccine (IIV) are currently available, with specific contraindications and precautions. 

The idea is to resume the current indications for vaccines in the vulnerable populations to support flu vaccination inclusiveness in anticipation of a universal vaccine strategy. In children with asthma, the flu vaccine is recommended, except for the live‐attenuated influenza virus that is contraindicated in patients between 2-4 years of age. It should be noted that inactivated influenza vaccine should be administered during breastfeeding or post‐partum, i.e. if not done during pregnancy. In patients with immunodeficiency and their close contacts and household members, an inactivated influenza vaccine is recommended. 

The live‐attenuated influenza virus is contraindicated in patients with suspected or confirmed immunodeficiency,  caregivers of severely affected immunodeficiency patients, and close contacts. Patients with severe immunodeficiency should minimize contact with live‐attenuated influenza virus–vaccinated healthcare providers for seven days after immunization.

Ref: https://onlinelibrary.wiley.com/doi/full/10.1111/pai.13338