Infectious Diseases — MCQs

Q: Treatment of whooping cough is

Erythromycin. ***Erythromycin*** - **Macrolide antibiotics** like erythromycin are the **first-line treatment** for whooping cough (*Bordetella pertussis*), especially when administered early in the catarrhal stage. - They work by **eradicating the bacteria**, **reducing the duration of infectiousness**, and can lessen the severity and duration of symptoms if given promptly. *Rifampicin* - **Rifampicin** is primarily used in the treatment of **tuberculosis** and other mycobacterial infections, not whooping cough. - Its mechanism of action involves inhibiting bacterial RNA synthesis, which is not the preferred strategy for *Bordetella pertussis*. *Tetracycline* - While **tetracyclines** are broad-spectrum antibiotics, they are generally **not recommended for whooping cough** due to potential side effects, particularly in young children (e.g., tooth discoloration). - Macrolides are superior and safer alternatives for *Bordetella pertussis* infection. *Ampicillin* - **Ampicillin** is a **beta-lactam antibiotic** commonly used for various bacterial infections, but it is **ineffective against *Bordetella pertussis***. - *Bordetella pertussis* shows resistance to penicillins and other beta-lactams, likely due to **beta-lactamase production** and the organism's location in the respiratory tract where beta-lactams may not achieve adequate bactericidal concentrations.

Q: At what age is the MMR vaccination typically administered?

One year. ***One year*** - The **first dose** of the MMR (measles, mumps, and rubella) vaccine is typically given to children between **12 and 15 months of age**. - This timing is chosen because maternal antibodies, which might interfere with vaccine effectiveness, generally wane by this age. - The **second dose** is administered between 4 and 6 years of age. *Incorrect: 1.5 years* - While some vaccination schedules may show 18 months as acceptable, the **standard recommendation for the first dose is earlier**, between 12-15 months. - Delaying beyond 15 months leaves children vulnerable to measles during a high-risk period. *Incorrect: 6 months* - Administering the MMR vaccine at 6 months is generally **not recommended** for routine first dose. - At this age, **maternal antibodies** can still be present, which might neutralize the vaccine and reduce its effectiveness. - However, in outbreak situations or before international travel, a dose may be given as early as 6 months (but must be repeated after 12 months). *Incorrect: 2 months* - At 2 months, infants receive other routine vaccines (DTaP, IPV, Hib, PCV, Rotavirus), but **not MMR**. - MMR is a **live attenuated vaccine** requiring a more mature immune system to mount an effective response. - Maternal antibodies present at 2 months would interfere with MMR vaccine effectiveness.

Practice by Chapter

Vaccine-Preventable Diseases

Practice Questions

Immunization Schedule

Practice Questions

Common Childhood Infections

Practice Questions

Pediatric HIV

Practice Questions

Congenital Infections

Practice Questions

Fever in Infants and Children

Practice Questions

Meningitis and Encephalitis

Practice Questions

Respiratory Tract Infections

Practice Questions

Gastrointestinal Infections

Practice Questions

Parasitic Infections

Practice Questions

Tuberculosis in Children

Practice Questions

Opportunistic Infections

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Scan to download app