Vaccination for 9-Month-Old with No Prior Immunizations (Saudi MOH Schedule)
For a 9-month-old infant with no previous vaccinations in Saudi Arabia, the necessary vaccines are DTaP, measles, BCG, Hepatitis B, and OPV, making option C the correct answer.
Rationale Based on Saudi Immunization Schedule
The Saudi Ministry of Health follows an immunization schedule that includes several vaccines by 9 months of age. For a completely unvaccinated 9-month-old, catch-up vaccination must address multiple antigens simultaneously 1, 2.
Core Vaccines Required at 9 Months
DTaP (Diphtheria, Tetanus, Pertussis): This infant needs to begin the DTaP series immediately, as the standard schedule calls for doses at 2,4, and 6 months 3, 4. For catch-up, the first dose should be given now with subsequent doses following minimum 4-week intervals 3.
BCG (Bacillus Calmette-Guérin): BCG is typically given at birth in Saudi Arabia and shows the highest coverage rates (97.5-99%) in national surveys 1, 2. This vaccine must be administered as part of catch-up immunization.
Hepatitis B: The hepatitis B series should have been initiated at birth with subsequent doses at 1-2 months and 6 months 3, 5. This infant requires the first dose immediately as part of catch-up vaccination.
OPV (Oral Polio Vaccine): While many countries use IPV exclusively, Saudi Arabia's schedule has historically included OPV 1, 2. The polio vaccination series (whether OPV or IPV) should be initiated immediately with doses following at appropriate intervals 3.
Measles vaccine: Measles vaccination is routinely given at 9 months in many settings, and Saudi surveys show measles coverage of 86-90% by this age 1, 2. Recent evidence supports measles vaccination as early as 6 months during outbreaks, with high seroconversion rates (94%) 6.
Why Other Options Are Incorrect
Option A (DTaP, BCag) is incomplete and contains a misspelling. It omits critical vaccines including measles, hepatitis B, and polio that should be administered at this visit 1, 2.
Option B (DTaP, BCG, IPV, OPV) omits measles vaccine, which is specifically indicated at 9 months, and hepatitis B, which is part of the routine schedule 3, 1.
Option D (DTaP, measles, MCV 4, OPV) incorrectly includes MCV4 (meningococcal conjugate vaccine), which is not indicated until age ≥2 years 3. It also omits BCG and hepatitis B.
Catch-Up Vaccination Strategy
For this unvaccinated 9-month-old, the provider should:
Administer all vaccines that can be safely given simultaneously at this visit, including DTaP, BCG, hepatitis B, OPV, and measles 3, 5.
Schedule follow-up doses with minimum 4-week intervals between DTaP doses 3, 4.
Complete the hepatitis B series with the second dose at least 4 weeks after the first, and the third dose at least 8 weeks after the second dose and at ≥24 weeks of age 5.
Ensure proper documentation to track the catch-up schedule and maintain high coverage rates as demonstrated in Saudi national surveys 1, 2.
Important Considerations
The Saudi MOH has achieved high immunization coverage rates (84.8-91.9% fully immunized by end of second year of life), demonstrating the effectiveness of their schedule 1, 2. However, vaccine hesitancy remains a concern, with 24% of healthcare providers expressing disagreement with the required schedule 7. Proper education about vaccine safety and efficacy is essential, as demonstrated by this parent's change of mind after receiving information 8, 7.