Table. Minimum acceptable age for the 1st dose of scheduled NIP-funded vaccines in infants

• If a child received their 1st dose of DTPa-containing vaccine between >28 days and <42 days (6 weeks) of age, it does not necessarily need to be repeated. Limited data suggest that receiving the vaccine at this age will still be safe and immunogenic. Follow the National Immunisation Program schedule for future doses, with the next dose of DTPa-containing vaccine given at 4 months of age.
• If a child received their 1st dose of DTPa-containing vaccine at ≤28 days of age, it is recommended that the dose is repeated. This repeat dose should ideally be given at 2 months of age. Follow the National Immunisation Program schedule for future doses, with the next dose of DTPa-containing vaccine given at 4 months of age.

• If a child receives their 1st dose of hepatitis A vaccine at <12 months of age, and they need ongoing protection against hepatitis A, repeat the 1st dose.

• As for DTPa

• As for DTPa

• If a child receives their 1st dose of either MenACWY or MenB vaccine between >28 days and <42 days (6 weeks) of age, the dose does not necessarily need to be repeated. Seek expert advice.
• The person’s age when they start the meningococcal vaccination course determines the number of doses required. See Meningococcal disease.
• Children should receive a dose of MenACWY vaccine at 12 months of age, even if they have received doses earlier in infancy. The Australian Immunisation Register will record a MenACWY vaccine given at ≥11 months of age as a valid dose to calculate immunisation status. A dose provided at ≥11 months (but before 12 months) of age may be sufficiently immunogenic. It is not necessary to repeat a dose if it was given at between ≥11 months and <12 months of age.

• Children can receive MMR vaccine from 6 months of age in certain circumstances, such as for post-exposure prophylaxis for measles (see Measles). It is recommended that the 1st dose be repeated if it was given at <11 months of age.
• It is not always necessary to repeat the first dose of MMR vaccine if it was given between 11 months and <12 months. The Australian Immunisation Register will record MMR vaccine given at ≥11 months of age as a valid dose to calculate immunisation status. A dose provided at ≥11 months (but before 12 months) of age may be sufficiently immunogenic, especially in infants born to mothers with measles antibody derived from vaccination rather than natural infection.
• MMRV vaccine is recommended as the 2nd (not 1st) dose of MMR-containing vaccine in children <18 months of age.
  
  If a child is inadvertently given MMRV vaccine as the 1st dose of MMR-containing vaccine, that MMR-containing dose does not need to be repeated, unless it was given at <11 months of age.

• If a child receives their 1st dose of PCV between >28 days and <42 days (6 weeks) of age, it does not necessarily need to be repeated. Limited data suggest that administration at this age will still be safe and immunogenic. Follow the National Immunisation Program schedule for future doses, with the next dose of PCV given at 4 months of age.
• If a child received their 1st dose of PCV at ≤28 days of age, it is recommended that the dose is repeated. This repeat dose should be given at 2 months of age. Follow the National Immunisation Program schedule for future doses, with the next dose of PCV given at 4 months of age.

• As for DTPa

• If a child receives their 1st dose of rotavirus vaccine between >28 days and <42 days (6 weeks) of age, it does not necessarily need to be repeated. Limited data suggest that administration at this age will still be safe and immunogenic. Follow the National Immunisation Program schedule for future doses, with the next dose of rotavirus vaccine given at 4 months of age.
• If a child receives their 1st dose of rotavirus vaccine at ≤28 days of age, it is recommended that the dose is repeated. This repeat dose should be given at 2 months of age. Follow the National Immunisation Program schedule for future doses, with the next dose of rotavirus vaccine given at 4 months of age.
• For all doses of rotavirus vaccine, do not exceed the upper age limits for dose administration. See Rotavirus.

• 1 monovalent varicella vaccine, Varilrix, is registered for use from 9 months of age. Children can receive Varilrix from ≥9 months of age in special circumstances, such as before travel.
• If the 1st dose of any varicella-containing vaccine is received at <12 months of age, the dose should be repeated, preferably at the scheduled age of 18 months.
• MMRV vaccine is recommended as the 2nd (not 1st) dose of MMR-containing vaccine in children <18 months of age. If a child is inadvertently given MMRV vaccine as the 1st dose of MMR-containing vaccine, that MMR-containing dose does not need to be repeated, unless it was given at <11 months of age.

Acronyms used:

• 13vPCV = 13-valent pneumococcal conjugate vaccine;
• 15vPCV = 15-valent pneumococcal conjugate vaccine;
• 20vPCV = 20-valent pneumococcal conjugate vaccine;
• DTPa = diphtheria-tetanus-acellular pertussis;
• Hib = Haemophilus influenzae type b;
• IPV = inactivated poliovirus;
• MenACWY = meningococcal ACWY;
• MenB = meningococcal B;
• MMR = measles-mumps-rubella;
• MMRV = measles-mumps-rubella-varicella