New vaccine offers protection for newborns against respiratory infections during pregnancy

From Nov 1, pregnant women can get a vaccine shot to protect infants against a viral respiratory infection with symptoms including cough and fever, which could lead to more serious conditions like pneumonia.

The Abrysvo vaccine protects infants – who are highly susceptible to respiratory syncytial virus (RSV) – against lower respiratory tract disease caused by the contagious virus, until they are six months old.

RSV symptoms include cough, fever and body aches, and can result in pneumonia and bronchiolitis – an inflammation of the small airways deep inside the lungs.

The jab can be given to women who are between 32 and 36 weeks pregnant, and the antibodies will be passed to their babies.

Abrysvo is manufactured by pharmaceutical giant Pfizer. It was approved by the Health Sciences Authority on July 23.

It is the first such vaccine to be approved for pregnant women in Singapore.

The vaccine will be progressively made available at private general practitioner clinics and hospitals, including KK Women’s and Children’s Hospital.

In response to queries, KKH said the cost of the vaccine has not been decided yet.

Abrysvo is administered in a single dose through an injection to a muscle in the arm.

Experts recommend mums-to-be get the vaccine because infants can be susceptible to the virus.

Contracting RSV during infancy may increase the risk of long-term consequences such as asthma and wheezing, said Dr Mohana Rajakulendran, a consultant paediatrician at the Petite Practice clinic in Joo Chiat.

Professor Anne Goh, a senior consultant of respiratory medicine service at KKH, said: “RSV infection is a common cause of bronchiolitis and pneumonia in early infancy, resulting in hospitalisation.

“So, if fewer babies are getting infected or have milder disease, they will not need hospitalisation or frequent visits to the doctor.”

While the vaccine is administered mainly to protect newborn infants, it can also protect pregnant women against RSV, added Prof Goh.

RSV is the leading cause of acute lower respiratory tract infection in children under five globally, and results in three million hospitalisations and 60,000 deaths annually, according to a study published in the medical journal Lancet.

In Singapore, the virus accounts for more than 3 per cent of the hospitalisations of infants under six months, a study published in the US Centres for Disease Control and Prevention found.

Dr Mohana said some babies of mums who received the vaccine were observed to have slightly lower weights at birth and a slight increased risk of jaundice. However, all babies remained healthy after delivery and did not experience major complications, she added.

Jaundice is a common condition in newborns, where their skin and eyes have a yellow tinge.

Prof Goh said that possible side effects that will be experienced by mothers who get vaccinated are usually mild, and can include headaches, muscle aches and soreness, redness or swelling at the injection site.

However, said Prof Tan Hak Koon, the chairman of the obstetrics and gynaecology division at KKH, those with a history of severe allergic reactions should not take the vaccine.

Severe reactions include anaphylaxis, a life-threatening reaction that often leads to respiratory collapse.

Those who are allergic to ingredients in the vaccine should also refrain from taking it, added Prof Tan.

Dr Mohana said mothers who have a history of pre-term deliveries, high blood pressure and pre-eclampsia should also be more cautious with taking the vaccine.

Patients with minor acute illnesses like a cold can still go and get the vaccine, added Prof Tan, but those with moderately serious to severe illnesses should hold off until their health improves.

Before getting the vaccine, mums-to-be should consult their obstetricians, said the doctors.

During clinical trials, Abrysvo demonstrated a 91.1 per cent effectiveness in preventing severe lower respiratory tract disease caused by RSV in infants in the first 90 days after birth, when administered to mothers when they were between 32 and 36 weeks pregnant.

In the first 180 days of birth, the vaccine demonstrated a 76.5 per cent effectiveness, said Pfizer.

Abrysvo has also been approved for those aged 60 and older. It is the second RSV vaccine made available in Singapore for the age group. GSK vaccine Arexvy was the first to be approved by the Singapore authorities in May 2024.

The Health Ministry said the vaccine is not included in immunisation schedules. It will continue to monitor data on the effectiveness and possible rare serious adverse events of the vaccine over time, it added.

This article was originally published on The Straits Times.