Enhancing Protection Against Influenza and COVID-19 for Pregnant Women and Medically at Risk Children

Pregnant women and children with chronic medical conditions are at increased risk of hospitalisation, intensive care admission and death from influenza and COVID-19 infections. However, there appears to be a high level of vaccine hesitancy among women of reproductive age. We will develop "nudge" interventions to improve influenza and COVID vaccine uptake and test the effectiveness of the interventions using randomised controlled trials in

* pregnant women
* medically at risk children.

Pregnant women and children with chronic medical conditions are at an unacceptable risk of hospitalisation and death from influenza and COVID-19 infections. Pregnant women are 3 times more likely to die from COVID-19 and over 7 times more likely to be admitted to an intensive care unit (ICU) with influenza compared to non-pregnant women. Children with chronic disease are already compromised with a higher risk of hospitalisation from influenza and requirement for ICU management and long term disability following COVID-19. Uptake of the recommended influenza vaccine among pregnant women and medically at risk children in Australia is only \~50%. Based on recent surveys, the predicted uptake of COVID-19 vaccine among both groups is also likely to be \~50%. These two groups preferentially receive care from medical specialists (obstetricians and paediatricians) and specialist nursing staff in hospitals, and are less likely to engage with primary care, the usual providers of immunisation.

The aim of this project is to develop a nudge (i.e. small changes in the environment that alter people's behaviour) and evaluate the effectiveness of the nudge intervention in improving the uptake of COVID and influenza vaccine by conducting four randomised control trials in

* pregnant women
* medically at risk children.

Eligibility Criteria:
Inclusion Criteria:

* COVID-19 pregnant women RCT: Pregnant women have received 2 or less doses of a recommended COVID-19 vaccine
* Influenza pregnant women RCT: Pregnant women have not received the influenza vaccine during pregnancy
* COVID-19 medically at risk children RCT: Medically at risk children aged 5 years to 18 years with a cardiac, endocrine, respiratory, gastrointestinal, haematological, musculoskeletal, neurological condition
* Influenza medically at risk children RCT: Children aged ≥6 months and \< 18 years with medical conditions specified in this list: immunocompromising conditions including malignancy, chronic steroid use, haematopoietic stem cell transplant; functional or anatomical asplenia including sickle cell disease or other haemoglobinopathies, congenital or acquired asplenia (for example, splenectomy) or hyposplenia; cardiac disease including cyanotic congenital heart disease, congestive heart failure, coronary artery disease; chronic respiratory conditions including suppurative lung disease, bronchiectasis, cystic fibrosis, chronic obstructive pulmonary disease, severe asthma (requiring frequent medical consultations or the use of multiple medicines); chronic neurological conditions including hereditary and degenerative CNS diseases, seizure disorders, spinal cord injuries, neuromuscular disorders; chronic metabolic disorders including Type 1 or 2 diabetes, amino acid disorders, carbohydrate disorders, cholesterol biosynthesis disorders, fatty acid oxidation defects, lactic acidosis, mitochondrial disorders, organic acid disorders, urea cycle disorders, vitamin/cofactor disorders, porphyria; chronic renal failure; children aged 5 to 10 years receiving long term aspiring therapy; Down syndrome; obesity (body mass index ≥30 kg/m2); children born less than 37 weeks gestation

Exclusion Criteria:

* COVID-19 pregnant women RCT: Pregnant women have contraindications to COVID-19 vaccines and already randomised to influenza RCT.
* Influenza pregnant women RCT: Pregnant women have contraindications to Influenza vaccines and already randomised to COVID-19 RCT.
* COVID-19 medically at risk children RCT:

  * Known contraindications to COVID-19 vaccine
  * Up to date for COVID-19 vaccine (≥ two doses) at the time of enrolment,
  * Sibling of a child already enrolled in the trial (only the sibling who is eligible and scheduled to attend a paediatric clinic first will be eligible)
  * Previous participation in the influenza nudge RCT
* Influenza medically at risk children RCT:

  * Known contraindications to influenza vaccine
  * Already received an influenza vaccine during the flu season in 2023
  * Sibling of a child already participating in the trial (the sibling who is eligible and scheduled to attend a paediatric clinic first will be eligible)
  * Previous participation in the COVID-19 nudge RCT