Rotavirus Vaccine:
The Oral Vaccine That Prevents Severe Diarrhoea

Most parents are surprised when they learn their baby will swallow a vaccine rather than receive an injection. The rotavirus vaccine is unique in the Singapore schedule — it is given as oral drops, not a jab. It is also the most time-sensitive vaccine your child will ever receive.

What Is Rotavirus?

Rotavirus is the world's most common cause of severe gastroenteritis (vomiting + diarrhoea) in infants and young children. Before the vaccine was introduced, rotavirus caused approximately 500,000 deaths per year globally in children under 5 — almost entirely in low- and middle-income countries where rehydration resources are limited.

In Singapore, rotavirus is a significant cause of infant hospitalisation, particularly among children in childcare and infant care settings where transmission is rapid. The virus spreads through the faecal-oral route — contaminated surfaces, hands, food — and is extremely stable in the environment.

Why Is It Dangerous?

The danger is not the vomiting or diarrhoea per se — it is the speed of dehydration. A small infant (under 6 months) can lose a critical proportion of their body fluid within hours of a severe rotavirus episode. Signs of dangerous dehydration in an infant:

• Sunken fontanelle (soft spot on top of head)
• Sunken eyes, no tears when crying
• Dry mouth and lips
• No wet nappy for 6–8 hours
• Listlessness or abnormal drowsiness

If any of these are present, go to the Children's Emergency — do not wait to see if they improve.

The Vaccine: Oral, Not Injectable

Rotarix (GSK) is given as a 1ml oral liquid squeezed into the baby's mouth — no needle. This is intentional: the rotavirus infects the gut, so an oral vaccine stimulates gut immunity most effectively. There are two options used in Singapore:

• Rotarix (GSK): 2 doses — at 2 months and 4 months
• RotaTeq (MSD): 3 doses — at 2, 4, and 6 months

After Vaccination

• Mild fussiness and loose stools for 1–2 days — normal
• Very rarely (~1–2 per 100,000 doses): intussusception — telescoping of the bowel. Signs: sudden severe inconsolable crying, legs drawn up to abdomen, vomiting, current-jelly stool. This is a medical emergency — go to A&E immediately.
• The vaccine virus can be shed in stools for a few weeks — practise good hand hygiene, especially if there are immunocompromised family members