Vaccine contraindications and precautions US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Vaccine contraindications and precautions. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Vaccine contraindications and precautions US Medical PG Question 1: A 28-year-old woman presents to her physician for follow-up. She was found to be HIV-positive 9 months ago. Currently she is on ART with lamivudine, tenofovir, and efavirenz. She has no complaints and only reports a history of mild respiratory infection since the last follow-up. She is also allergic to egg whites. Her vital signs are as follows: the blood pressure is 120/75 mm Hg, the heart rate is 73/min, the respiratory rate is 13/min, and the temperature is 36.7°C (98.0°F). She weighs 68 kg (150 lb), and there is no change in her weight since the last visit. On physical examination, she appears to be pale, her lymph nodes are not enlarged, her heart sounds are normal, and her lungs are clear to auscultation. Her total blood count shows the following findings:
Erythrocytes 3.2 x 106/mm3
Hematocrit 36%
Hgb 10 g/dL
Total leukocyte count 3,900/mm3
Neutrophils 66%
Lymphocytes 24%
Eosinophils 3%
Basophils 1%
Monocytes 7%
Platelet count 280,000/mm3
Her CD4+ cell count is 430 cells/µL. The patient tells you she would like to get an influenza vaccination as flu season is coming. Which of the following statements is true regarding influenza vaccination in this patient?
- A. As long as the patient is anemic, she should not be vaccinated.
- B. Influenza vaccination is contraindicated in HIV-positive patients because of the serious complications they can cause in immunocompromised people.
- C. Inactivated or recombinant influenza vaccines fail to induce a sufficient immune response in patients with CD4+ cell counts under 500 cells/µL.
- D. Nasal-spray influenza vaccine is the best option for vaccination in this patient.
- E. The patient can receive approved recombinant or inactivated influenza vaccines, with egg-free formulations preferred due to her egg allergy. (Correct Answer)
Vaccine contraindications and precautions Explanation: **The patient can receive approved recombinant or inactivated influenza vaccines, with egg-free formulations preferred due to her egg allergy.**
- Patients with HIV, regardless of their CD4+ count, should receive the **inactivated influenza vaccine** annually due to their increased risk of severe influenza complications.
- Given the patient's reported egg allergy, an **egg-free vaccine formulation**, such as a recombinant injectable influenza vaccine (RIV4) or cell-culture-based inactivated influenza vaccine (ccIIV4), is the preferred choice to minimize allergic reactions.
*As long as the patient is anemic, she should not be vaccinated.*
- **Anemia** is not a contraindication for receiving the influenza vaccine; the benefits of vaccination typically outweigh any risks associated with mild anemia.
- While the patient is anemic (Hgb 10 g/dL), this condition does not prevent her from safely receiving an **inactivated influenza vaccine**.
*Influenza vaccination is contraindicated in HIV-positive patients because of the serious complications they can cause in immunocompromised people.*
- This statement is incorrect; **inactivated influenza vaccines** are recommended for HIV-positive individuals, as they are not live vaccines and cannot cause influenza.
- HIV-positive patients are at higher risk for severe influenza complications, making vaccination even more crucial, not contraindicated.
*Inactivated or recombinant influenza vaccines fail to induce a sufficient immune response in patients with CD4+ cell counts under 500 cells/µL.*
- While the immune response to vaccines can be attenuated in HIV patients with lower CD4+ counts, even a partial response offers some protection and is better than no vaccination.
- The **guidelines for HIV patients** recommend influenza vaccination regardless of CD4+ count, emphasizing the importance of any induced immunity.
*Nasal-spray influenza vaccine is the best option for vaccination in this patient.*
- The **nasal-spray influenza vaccine (LAIV)** is a **live-attenuated vaccine**, which is generally contraindicated in immunocompromised individuals, including those with HIV, due to the risk of active infection.
- HIV patients should receive **inactivated or recombinant influenza vaccines**, not live-attenuated formulations.
Vaccine contraindications and precautions US Medical PG Question 2: An 11-year-old boy is brought to his pediatrician by his parents for the routine Tdap immunization booster dose that is given during adolescence. Upon reviewing the patient’s medical records, the pediatrician notes that he was immunized according to CDC recommendations, with the exception that he received a catch-up Tdap immunization at the age of 8 years. When the pediatrician asks the boy’s parents about this delay, they inform the doctor that they immigrated to this country 3 years ago from Southeast Asia, where the child had not been immunized against diphtheria, tetanus, and pertussis. Therefore, he received a catch-up series at 8 years of age, which included the first dose of the Tdap vaccine. Which of the following options should the pediatrician choose to continue the boy’s immunization schedule?
- A. A single dose of Td vaccine at 18 years of age
- B. A single dose of Td vaccine now
- C. No further vaccination needed
- D. A single dose of Tdap vaccine now
- E. A single dose of Tdap vaccine at 13 years of age (Correct Answer)
Vaccine contraindications and precautions Explanation: ***A single dose of Tdap vaccine at 13 years of age***
- The CDC recommends a **minimum interval of 5 years** between Tdap doses when Tdap is given as part of a catch-up series.
- Since this patient received his first Tdap at age 8, the earliest he should receive the adolescent booster is at **age 13** (5 years later).
- This timing ensures adequate spacing while still providing the recommended adolescent booster for **pertussis, tetanus, and diphtheria** protection.
- The 5-year interval prevents excessive antigen exposure and optimizes immune response.
*A single dose of Tdap vaccine now*
- Giving Tdap now would result in only a **3-year interval** from the previous Tdap dose at age 8.
- This violates the CDC recommendation of a **minimum 5-year interval** between Tdap doses.
- Shorter intervals may increase local reactogenicity without improving protection.
*A single dose of Td vaccine now*
- While this would provide tetanus and diphtheria protection, it would **not protect against pertussis**, which is a critical component of adolescent vaccination.
- The Tdap vaccine is specifically recommended for adolescents to boost waning pertussis immunity.
- Additionally, giving it now would still be earlier than the recommended 5-year interval from the previous pertussis-containing vaccine.
*A single dose of Td vaccine at 18 years of age*
- This option would result in a **10-year gap** from the last pertussis-containing vaccine, leaving the adolescent vulnerable during high-risk years.
- The adolescent Tdap booster is specifically timed for ages 11-13 to protect during peak transmission periods in middle and high school.
- Waiting until 18 would miss the critical window for pertussis protection.
*No further vaccination needed*
- While the patient completed a catch-up series, the CDC still recommends an **adolescent Tdap booster** even for those who received Tdap in a catch-up series.
- The adolescent booster is important to maintain immunity against pertussis, which wanes significantly over time.
- The booster should be given at age 13 to maintain the 5-year minimum interval.
Vaccine contraindications and precautions US Medical PG Question 3: A 24-year-old woman with HIV infection comes to the physician for a follow-up examination. She has been inconsistently taking combined antiretroviral therapy for the past 5 years. She did not receive any childhood vaccinations because her parents were against them. During the consultation, the patient says that she wants to catch up on the missed vaccinations. Laboratory studies show a CD4+ T lymphocyte cell count of 180/mm3. Administration of the vaccine against which of the following agents should be avoided in this patient?
- A. Clostridium tetani
- B. Human papillomavirus
- C. Varicella zoster virus (Correct Answer)
- D. Bordetella pertussis
- E. Haemophilus influenzae
Vaccine contraindications and precautions Explanation: ***Varicella zoster virus***
- The **varicella zoster vaccine is a live attenuated vaccine**, which is generally contraindicated in individuals with severe **immunodeficiency**, such as HIV patients with a **CD4+ count below 200 cells/mm³**.
- Administering a live vaccine to an immunocompromised patient can lead to **uncontrolled viral replication** and potentially cause the disease it is meant to prevent.
*Clostridium tetani*
- The **tetanus vaccine** is a **toxoid vaccine**, meaning it contains inactivated bacterial toxins, not live organisms.
- It is **safe and recommended** for individuals with HIV, regardless of their CD4+ count, to provide protection against tetanus.
*Human papillomavirus*
- The **HPV vaccine** is a **recombinant vaccine**, consisting of viral-like particles (VLPs) and containing no live virus.
- It is **safe and recommended** for HIV-positive individuals and helps prevent HPV-related cancers.
*Bordetella pertussis*
- The **pertussis vaccine** (part of DTaP or Tdap) is an **acellular vaccine**, containing purified bacterial components, not live bacteria.
- It is **safe and recommended** for HIV patients to protect against whooping cough.
*Haemophilus influenzae*
- The **Haemophilus influenzae type b (Hib) vaccine** is a **conjugate vaccine**, made from bacterial capsular polysaccharide linked to a carrier protein.
- It is **safe and recommended** for HIV-positive individuals, as they are at increased risk for invasive Hib disease.
Vaccine contraindications and precautions US Medical PG Question 4: A 20-year-old primigravid woman comes to the physician in October for her first prenatal visit. She has delayed the visit because she wanted a “natural birth” but was recently convinced to get a checkup after feeling more tired than usual. She feels well. Menarche was at the age of 12 years and menses used to occur at regular 28-day intervals and last 3–7 days. The patient emigrated from Mexico 2 years ago. Her immunization records are unavailable. Pelvic examination shows a uterus consistent in size with a 28-week gestation. Laboratory studies show:
Hemoglobin 12.4 g/dL
Leukocyte count 8,000/mm3
Blood group B negative
Serum
Glucose 88 mg/dL
Creatinine 1.1 mg/dL
TSH 3.8 μU/mL
Rapid plasma reagin negative
HIV antibody negative
Hepatitis B surface antigen negative
Urinalysis shows no abnormalities. Urine culture is negative. Chlamydia and gonorrhea testing are negative. A Pap smear is normal. Administration of which of the following vaccines is most appropriate at this time?
- A. Varicella and influenza
- B. Varicella and Tdap
- C. Influenza only
- D. Tdap and influenza (Correct Answer)
- E. Hepatitis B and MMR
Vaccine contraindications and precautions Explanation: ***Tdap and influenza***
- The **Tdap vaccine** is recommended for pregnant women during each pregnancy, preferably between **27 and 36 weeks gestation**, to provide passive immunity to the newborn against pertussis. The patient is at 28 weeks gestation.
- The **influenza vaccine** is recommended for all pregnant women, regardless of trimester, during flu season (October in this case) to protect both the mother and the newborn.
*Varicella and influenza*
- The **varicella vaccine is contraindicated in pregnancy** because it is a live attenuated vaccine.
- While influenza vaccine is appropriate, administering varicella vaccine is not.
*Varicella and Tdap*
- As mentioned, the **varicella vaccine is contraindicated in pregnancy** due to its live attenuated nature.
- Although Tdap is appropriate, varicella is not.
*Influenza only*
- While the **influenza vaccine is appropriate**, the **Tdap vaccine** is also indicated for this patient given her gestational age and the benefits for the newborn.
- Administering only influenza would miss an opportunity to provide crucial pertussis protection.
*Hepatitis B and MMR*
- The **Hepatitis B vaccine** is safe in pregnancy if indicated, but the patient tested **Hepatitis B surface antigen negative**, suggesting no current infection and no immediate need for vaccination based on the provided information.
- The **MMR vaccine is contraindicated in pregnancy** because it is a live attenuated vaccine.
Vaccine contraindications and precautions US Medical PG Question 5: A 6-year-old girl presents to the clinic for a general checkup before her last scheduled DTaP vaccination. Her mother is concerned about mild swelling and redness at the site of injection after her daughter’s previous DTaP administration. The patient has mild spastic cerebral palsy. She was diagnosed with epilepsy at the age of 5, and it is well-controlled with levetiracetam. She is allergic to penicillin. Currently, she complains of malaise and mild breathlessness. The mother noted that her daughter has been sluggish for the last 3 days. Her vital signs are as follows: the blood pressure is 100/60 mm Hg, the heart rate is 90/min, the respiratory rate is 22/min, and the temperature is 38.8°C (101.8°F). On physical examination, the patient has slightly enlarged submandibular lymph nodes bilaterally and oropharyngeal erythema. On auscultation, there are diminished vesicular breath sounds with a few respiratory crackles over the lower lobe of the left lung. Which of the following factors requires delaying the patient’s vaccination?
- A. Cerebral palsy
- B. Mild swelling and redness at the site of injection after the previous vaccine administration
- C. Signs of pneumonia (Correct Answer)
- D. Penicillin allergy
- E. Epilepsy
Vaccine contraindications and precautions Explanation: ***Signs of pneumonia***
- The patient's symptoms (malaise, breathlessness, fever, submandibular lymphadenopathy, oropharyngeal erythema, diminished breath sounds, and crackles) are indicative of an **acute, moderate-to-severe illness**, most likely pneumonia.
- A definitive acute illness, such as suspected pneumonia, is a **precaution** for vaccine administration, warranting a delay until symptoms resolve to avoid attributing worsening symptoms to the vaccine or compounding the illness.
- Per **CDC/ACIP guidelines**, moderate-to-severe acute illness (with or without fever) is a precaution for all vaccines.
*Cerebral palsy*
- **Cerebral palsy** is a chronic, stable neurological condition and is generally **not a contraindication or precaution** for routine vaccinations, including DTaP.
- Patients with cerebral palsy should receive recommended vaccines to prevent infectious diseases, as they may be at increased risk for complications from these infections.
*Mild swelling and redness at the site of injection after the previous vaccine administration*
- **Mild local reactions** (redness, swelling, tenderness) at the injection site are common and **expected side effects** of many vaccines, including DTaP.
- Such mild reactions are **not considered a contraindication or precaution** for subsequent doses.
*Penicillin allergy*
- An allergy to penicillin is generally **not relevant** to vaccine administration, as vaccines do not contain penicillin or related antibiotics.
- The DTaP vaccine does not contain components that would cross-react with a penicillin allergy.
*Epilepsy*
- **Well-controlled epilepsy**, especially when managed with medication like levetiracetam, is **not a contraindication or precaution** for vaccination.
- Most vaccines are safe for individuals with epilepsy, and the benefit of preventing infectious diseases outweighs any theoretical risk.
Vaccine contraindications and precautions US Medical PG Question 6: A young man about to leave for his freshman year of college visits his physician in order to ensure that his immunizations are up-to-date. Because he is living in a college dormitory, his physician gives him a vaccine that prevents meningococcal disease. What type of vaccine did this patient likely receive?
- A. Live, attenuated
- B. Killed, attenuated
- C. Toxoid
- D. Conjugated polysaccharide (Correct Answer)
- E. Killed, inactivated
Vaccine contraindications and precautions Explanation: ***Conjugated polysaccharide***
- The **meningococcal vaccine** commonly administered to college students is a **polysaccharide vaccine** wherein the polysaccharide antigens are conjugated to a protein carrier.
- This **conjugation** improves the immune response by converting a T-independent antigen into a T-dependent one, inducing better memory responses and allowing for vaccination of infants.
*Live, attenuated*
- Live, attenuated vaccines contain a **weakened form of the pathogen** that can replicate but does not cause disease, such as the MMR or varicella vaccine.
- While they elicit strong, long-lasting immunity, the meningococcal vaccine is not typically of this type due to the risk of opportunistic infection, especially in immunocompromised individuals.
*Killed, attenuated*
- This term is a **contradiction**; vaccines are either **killed (inactivated)** or **live (attenuated)**, but not both.
- Attenuation implies weakening, for which the organism would still be alive.
*Toxoid*
- **Toxoid vaccines** are made from inactivated bacterial toxins, used to protect against diseases where the toxin, not the bacterium itself, causes the disease, such as diphtheria and tetanus.
- Meningococcal disease is primarily caused by **direct bacterial invasion and inflammation**, not solely by a toxin.
*Killed, inactivated*
- **Killed, inactivated vaccines** contain whole pathogens that have been killed and cannot replicate, such as the inactivated poliovirus vaccine.
- While there are inactivated meningococcal vaccines, the most common type for broad use, especially in college settings, is the conjugated polysaccharide vaccine, which elicits a stronger and more long-lasting immune response against multiple serotypes compared to plain inactivated whole-cell vaccines.
Vaccine contraindications and precautions US Medical PG Question 7: A 24-year-old newly immigrated mother arrives to the clinic to discuss breastfeeding options for her newborn child. Her medical history is unclear as she has recently arrived from Sub-Saharan Africa. You tell her that unfortunately she will not be able to breastfeed until further testing is performed. Which of the following infections is an absolute contraindication to breastfeeding?
- A. Human Immunodeficiency Virus (HIV) (Correct Answer)
- B. Latent tuberculosis
- C. Hepatitis B
- D. Hepatitis C
- E. All of the options
Vaccine contraindications and precautions Explanation: ***Human Immunodeficiency Virus (HIV)***
- In developed countries where safe alternatives are available, **HIV-positive mothers** are advised against breastfeeding due to the risk of **vertical transmission** through breast milk.
- This is considered an **absolute contraindication** in settings where formula feeding is accessible and safe.
*Latent tuberculosis*
- **Latent tuberculosis** is not a contraindication to breastfeeding; mothers can breastfeed while receiving treatment.
- Active, untreated tuberculosis, however, generally requires temporary separation of mother and child until the mother is no longer infectious, but pumping and feeding expressed milk is often still an option.
*Hepatitis B*
- **Hepatitis B** infection in the mother is not a contraindication to breastfeeding, especially if the infant receives **hepatitis B vaccine** and **Hepatitis B Immune Globulin (HBIG)** at birth.
- Breastfeeding is considered safe and does not increase the risk of transmission to the infant.
*Hepatitis C*
- **Hepatitis C** is generally **not a contraindication** to breastfeeding, as studies have shown a very low risk of transmission through breast milk.
- Breastfeeding is supported unless the mother has **cracked or bleeding nipples**, which could potentially allow viral transmission.
*All of the options*
- This option is incorrect because **only HIV** is considered an absolute contraindication to breastfeeding in settings where safe alternatives are available.
- Latent TB, Hepatitis B, and Hepatitis C alone do not preclude breastfeeding.
Vaccine contraindications and precautions US Medical PG Question 8: A 12-month-old boy presents for a routine checkup. The patient immigrated from the Philippines with his parents a few months ago. No prior immunization records are available. The patient’s mother claims that he had a series of shots at 6 months of age which gave him a severe allergic reaction with swelling of the tongue and the face. She also remembers that he had the same reaction when she introduced solid foods to his diet, including carrots, eggs, and bananas. Which of the following vaccinations are not recommended for this patient?
- A. Measles, mumps, and rubella (MMR) vaccine
- B. Hepatitis B vaccine
- C. Varicella vaccine
- D. Intranasal influenza vaccine
- E. Intramuscular influenza vaccine (Correct Answer)
Vaccine contraindications and precautions Explanation: ***Important Note on Current Guidelines***
Based on **current CDC/ACIP guidelines (2023-2024)**, egg allergy alone is **no longer a contraindication** to influenza vaccines. However, this question tests knowledge of vaccine safety in the context of **severe anaphylaxis to a prior vaccination**.
***Intramuscular influenza vaccine***
- **Historically**, this was considered the most concerning option for patients with severe egg allergy, as many influenza vaccines were produced using egg-based culture methods
- **Current practice**: Per CDC guidelines, persons with egg allergy of any severity can receive any age-appropriate influenza vaccine, as egg protein content is minimal or absent in modern formulations
- However, if this patient had a **documented anaphylactic reaction to the influenza vaccine itself** (not just eggs), then it would be contraindicated
- Given the timing (6 months) and symptoms described, this represents the **historically correct answer**, though modern practice has evolved
*Measles, mumps, and rubella (MMR) vaccine*
- MMR vaccine is grown in **chick embryo fibroblast cells**, NOT in eggs, and contains **no egg protein**
- **Safe for patients with egg allergy** - no contraindication based on egg allergy
- Should be administered on schedule for catch-up immunization
*Hepatitis B vaccine*
- Produced using **recombinant DNA technology in yeast cells**
- Contains **no egg protein** and no animal-derived proteins
- **No contraindication** for this patient - safe to administer
*Varicella vaccine*
- Grown in **human diploid cell cultures**, NOT in eggs
- Contains **no egg protein**
- **Safe for patients with egg allergy** - no contraindication
- Should be administered as part of catch-up immunization
*Intranasal influenza vaccine (LAIV)*
- Like the intramuscular formulation, **current guidelines allow administration** to patients with egg allergy of any severity
- Contains similar or less egg protein than inactivated vaccines in modern formulations
- **Not contraindicated** based solely on egg allergy per current CDC guidelines
Vaccine contraindications and precautions US Medical PG Question 9: A 4-month-old boy is brought to the physician by his parents for a well-child examination. He has cystic fibrosis diagnosed by newborn screening. His parents report frequent feedings and large-volume and greasy stools. His 4-year-old brother has autism. Current medications include bronchodilators, pancreatic enzyme supplements, and fat-soluble vitamins. He is at the 18th percentile for height and 15th percentile for weight. Scattered wheezes are heard throughout both lung fields. Examination shows a distended and tympanic abdomen with no tenderness or guarding. Which of the following is a contraindication for administering one or more routine vaccinations?
- A. Allergy to egg protein
- B. History of cystic fibrosis
- C. History of febrile seizures
- D. Fever of 38.2°C (100.7°F) following previous vaccinations
- E. History of intussusception (Correct Answer)
Vaccine contraindications and precautions Explanation: ***History of intussusception***
- A history of **intussusception** is a **contraindication for rotavirus vaccine** administration, as the vaccine itself has a small risk of intussusception, particularly with the first dose.
- The rotavirus vaccine is part of routine childhood immunizations, so this would be a contraindication for one of the routine vaccines.
*Allergy to egg protein*
- Egg allergy is a contraindication primarily for yellow fever vaccine and some influenza vaccines, which are typically not routine vaccinations for a 4-month-old. Many flu vaccines are egg-free or can be safely administered to those with egg allergy under supervision.
- The MMR vaccine is generally safe for those with egg allergy since the amount of egg protein is negligible.
*History of cystic fibrosis*
- **Cystic fibrosis** itself is **not a contraindication** to routine vaccinations; in fact, patients with chronic conditions like CF are often *more* encouraged to receive vaccinations to prevent severe infections.
- The patient's symptoms (poor growth, greasy stools, wheezing) are manifestations of CF, not reasons to defer vaccination.
*History of febrile seizures*
- A history of **febrile seizures** is generally **not a contraindication** to routine vaccinations.
- Parents should be counseled on fever management after vaccination, but the risk of recurrent febrile seizures is not increased by vaccination to a level that warrants deferral.
*Fever of 38.2°C (100.7°F) following previous vaccinations*
- A **low-grade fever** after vaccination is a common and **expected immune response**, not a contraindication for future doses.
- Only a **severe allergic reaction** (e.g., anaphylaxis) to a previous dose of a vaccine or one of its components is a contraindication to subsequent doses of that specific vaccine.
Vaccine contraindications and precautions US Medical PG Question 10: A 34-year-old man comes to the physician for a routine health maintenance examination. He was diagnosed with HIV 8 years ago. He is currently receiving triple antiretroviral therapy. He is sexually active and uses condoms consistently. He is planning a trip to Thailand with his partner to celebrate his 35th birthday in 6 weeks. His last tetanus and diphtheria booster was given 4 years ago. He received three vaccinations against hepatitis B 5 years ago. He had chickenpox as a child. Other immunization records are unknown. Vital signs are within normal limits. Cardiopulmonary examination shows no abnormalities. Leukocyte count shows 8,700/mm3, and CD4+ T-lymphocyte count is 480 cells/mm3 (Normal ≥ 500); anti-HBs is 150 mIU/mL. Which of the following recommendations is most appropriate at this time?
- A. Yellow fever vaccine
- B. Hepatitis B vaccine
- C. Tetanus, diphtheria, pertussis vaccine (Tdap)
- D. Measles, mumps, rubella vaccine
- E. No vaccination (Correct Answer)
Vaccine contraindications and precautions Explanation: ***Correct: No vaccination***
- Given the patient's current immunization status and clinical scenario, **none of the listed vaccines are indicated at this time**.
- His CD4+ count of 480 cells/mm³ indicates relatively preserved immune function on effective antiretroviral therapy.
- His **anti-HBs level of 150 mIU/mL** demonstrates **adequate hepatitis B immunity** (protective level ≥10 mIU/mL).
- His **tetanus-diphtheria booster was given 4 years ago**, and routine boosters are recommended every **10 years**, so he is not due for another 6 years.
*Incorrect: Yellow fever vaccine*
- **Thailand is not a yellow fever endemic country**, so yellow fever vaccination is **not required or recommended** for travel there.
- Yellow fever vaccine is a **live attenuated vaccine** that can be given to HIV-positive patients with **CD4+ counts ≥200 cells/mm³** when travel to endemic areas (parts of Africa and South America) is necessary.
- Since the patient has a CD4+ count of 480 and Thailand doesn't require this vaccine, this is not applicable.
*Incorrect: Hepatitis B vaccine*
- The patient's **anti-HBs level of 150 mIU/mL** indicates **adequate protective immunity** against hepatitis B.
- A level ≥10 mIU/mL is considered protective, so **no booster is needed**.
*Incorrect: Tetanus, diphtheria, pertussis vaccine (Tdap)*
- **Tetanus-diphtheria boosters are recommended every 10 years**.
- The patient received his last booster **4 years ago**, so he is **not due** for another booster at this time.
- There is no specific indication for **pertussis vaccination** (e.g., pregnancy, close contact with infants).
*Incorrect: Measles, mumps, rubella vaccine*
- **MMR is a live attenuated vaccine** that is **contraindicated** in HIV-positive individuals with **CD4+ counts <200 cells/mm³**.
- While this patient's CD4+ count is 480, MMR should only be given to HIV patients if they lack immunity and have CD4 ≥200.
- There is **no documented need** for MMR based on the clinical scenario provided, and his immunity status to these infections is unknown.
- Without evidence of susceptibility or specific exposure risk, vaccination is not indicated.
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