RANZCOG guideline - flu in pregnancy

Question 1

what is the NNT of the flu vax to prevent one maternal or neonatal respiratory illness?

Answer 1

1:5

Question 2

Why does the flu vax need to be given each year

Answer 2

the 2 common strains - A and B have H and N antigens that change their structure
each vaccine has to be updated to the relevant vaccine for current pandemic

Question 3

What are the H and N antigens of the flu vaccine?

Answer 3

H = Haemagluttinin antigen
N = Neuraminidase antigen
frequently change their protein structure resulting in new vaccine requirements

Question 4

are there any adverse effects of the influenza vaccine when given in pregnancy?

Answer 4

no study to date has shown any adverse consequence of the flu vaccine - neither maternal nor fetal

Question 5

does the influenza vaccine confer any protection for infants?

Answer 5

• active placental transfer of maternal antibodies results in protection for up to 6 months for the infant

Question 6

how long after the influenza vaccination can protection be expected?

Answer 6

2 weeks - seroconversion usually takes 4-6 weeks