Influenza or seasonal flu is cause by a virus, namely Influenza A or B.  To most healthy people, flu is an unpleasant experience characterized by symptoms of fever, muscle pain, nasal congestion and discharge.  It is usually a self-limiting disease and recovery is expected within a week.  Pregnant mothers, those with pre-existing medical condition, the very young and old population are prone to the more serious complications of influenza infection.  These complications include bronchitis, pneumonia, ear infection, sepsis, meningitis and encephalitis.

Influenza vaccine – risks and benefits

There is strong evidence that influenza vaccination for women who are pregnant is both efficacious and safe, with no increased incidence of miscarriages, fetal anomalies or neurodevelopmental disorders (Tamma 2009). There is also evidence that infants born to mothers vaccinated against influenza during pregnancy, compared with those not vaccinated, had lower rates of laboratory-confirmed influenza (4% versus 10%) and febrile respiratory illness (69% versus 97%) up to 24 months of age (Zaman K 2008).

The influenza vaccine can be safely taken at any stage of the pregnancy.  The injectable vaccine consists of inactivated virus (harmless as it does not contain live virus) and is not associated with adverse maternal or fetal outcome. The vaccine needs to be repeated annually due to the rapid viral mutation.  Its reported effectiveness is between 25-75%.

Despite the above benefits, the current vaccine uptake by pregnant mothers are low.  This is partly due to safety concern, poor patient awareness and lack of healthcare professional recommendation Koul 2014).


Pregnant women are at high risk of morbidity and mortality from influenza infection.  The current professional consensus strongly advocates influenza vaccine in pregnancy (ACOG 2014, RANZCOG 2014,WHO).

(Notes: At the time of writing, there is no known local guideline on influenza vaccine in pregnancy.)



ACOG committee Opinion 608. Influenza vaccination during pregnancy. Obstet Gynecol 2014

Koul PA et al., Poor uptake of influenza vaccination in pregnancy in northern India. Int J Obstet Gynecol 2014

RANZCOG. College statement: Influenza vaccine during pregnancy 2013.

Tamma PD et al., Safety of influenza vaccination during pregnancy. Am J Obstet Gynecol. 2009.

World Health Organization. Influenza (seasonal) fact sheet number 211.

Zaman K et al., Effectiveness of maternal influenza immunization in mothers and infants. NEJM 2008.


Author: Dr Ng Soon Pheng

Dr. Ng Soon Pheng MD(USM), M.Med (O&G), Fellow Reprod Medicine (Singapore), AM (Mal) Dr. Ng Soon Pheng qualified from University Kebangsaan Malaysia (UKM), Malaysia. After obtaining his post graduate degree, Dr. Ng Soon Pheng continued his clinical fellowship training in the field of IVF in Singapore. He was also the recipient of Yayasan Sultan Iskandar (Johor) Scholarship for the fellowship stint. Dr. Ng Soon Pheng has more than 10 years of working experience in the field of Obstetrics and Gynaecology in the public and university hospital, with special interests in infertility. He was an Associate Professor with the Department of O&G in Universiti Kebangsaan Malaysia (UKM) specialising in infertility. Dr. Ng Soon Pheng is currently Consultant Obstetrician and Gynaecologist with special interests in infertility at Columbia Asia Hospital - Puchong.