# A 15-month-old child received the MMR (measles, mumps, rubella) vaccine 8 days ago. The parent calls the clinic reporting that the child has developed a fever of 101.2°F (38.4°C) and a rash on the trunk. What is the most appropriate nursing response?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=541777  
> language: ko  
> subject: Growth & Development

## 문제

A 15-month-old child received the MMR (measles, mumps, rubella) vaccine 8 days ago. The parent calls the clinic reporting that the child has developed a fever of 101.2°F (38.4°C) and a rash on the trunk. What is the most appropriate nursing response?

## 보기

1. Advise the parent to bring the child to the emergency department immediately for evaluation of a severe reaction.
2. Recommend giving the child acetaminophen and scheduling an appointment within 24 hours to rule out measles.
3. Explain that these symptoms are expected vaccine reactions and provide comfort measures while monitoring for severe symptoms. **✔ 정답**
4. Instruct the parent to discontinue all future vaccinations due to this adverse reaction to the MMR vaccine.

**정답: 3**

## 해설

MMR vaccine can cause mild fever and rash 7-12 days post-vaccination as a normal immune response. Advise comfort measures and monitoring for severe symptoms.

## 심화 해설

Understanding the Live Vaccine Response

The MMR vaccine is a combined attenuated (weakened) live viral vaccine. When administered, these weakened viruses must replicate within the body to stimulate a protective immune response. This replication process is not immediate; it takes time for the viral load to increase sufficiently to trigger the immune system's noticeable reaction. Typically, this manifests clinically 5 to 12 days after vaccination. The symptoms the parent is observing—a fever of 38.4°C and a trunkal rash—occurring 8 days post-immunization, fall perfectly within this expected window. These are not signs of a severe allergic reaction, which would occur within minutes to hours, nor are they indicative of wild-type measles infection, but rather a mild, predictable manifestation of the body's immune activation [1].

Differentiating Expected Reaction from Adverse Event

It is critical to distinguish between a common, self-limiting vaccine reaction and a true adverse event following immunization (AEFI). The safety surveillance data for the MMR vaccine, as analyzed in large-scale studies, consistently identifies fever and rash as the most frequently reported systemic reactions. These are categorized as non-serious, expected events. A true adverse event would involve symptoms beyond this mild, self-limiting picture, such as high fever unresponsive to antipyretics, a rapidly spreading or purpuric rash, respiratory distress, or significant behavioral changes like inconsolable crying or lethargy. The clinical presentation described by the parent—a moderate fever and a localized rash—is a classic example of the vaccine virus replication phase and does not constitute a safety signal requiring emergency intervention or discontinuation of the vaccination schedule [1].

Clinical Management and Parent Education

The most appropriate nursing response is rooted in evidence-based reassurance and supportive care. The parent should be educated that this is a positive sign that the child's immune system is responding appropriately to the vaccine. Management focuses on comfort: recommending age-appropriate doses of acetaminophen for the fever, encouraging fluid intake, and advising the use of lightweight clothing. Crucially, the nurse must provide clear safety netting by describing the specific signs of a severe reaction that would warrant immediate medical attention, such as a seizure, extreme lethargy, or a rash that progresses to petechiae or purpura. This approach validates the parent's concern, provides actionable guidance, and reinforces confidence in the immunization program without unnecessarily alarming the parent or compromising the child's future vaccination schedule [1].References (research sources)

- [1]Safety Analysis of Simultaneous Vaccination of Japanese Encephalitis Attenuated Live Vaccine and Measles, Mumps, and Rubella Combined Attenuated Live Vaccine from 2020 to 2023 in Guangzhou, China.Research articleLiu J, Huang Y, Jing F, Kang Y, Liu Q, Zheng Z, Zhang C, Liang X, Zhang Z. (2025) · DOI: 10.3390/vaccines13040417

## 임상 시나리오

MMR Post-Vaccination: Fever & Rash TriageExpected Reaction vs. Adverse Event
The MMR vaccine is a live attenuated virus. Systemic symptoms like fever (38.4°C) and a maculopapular rash on the trunk appearing 5–12 days post-injection are expected, self-limiting reactions from viral replication, not anaphylaxis or measles infection.

Nursing management focuses on parental reassurance, comfort measures (antipyretics for fever, light clothing), and safety netting. Advise the parent to monitor for severe signs: fever lasting >72 hours, purpuric rash, lethargy, or respiratory distress, which require immediate evaluation.

CautionDo not advise discontinuing the vaccination series. This expected reaction is not a contraindication. The child remains at risk for measles, mumps, and rubella if the second dose is withheld.

## 핵심 개념

- **Live Attenuated Vaccine** — A vaccine using weakened forms of the virus that replicate to stimulate immunity, often causing mild, delayed symptoms mimicking natural infection.
- **MMR Vaccine Reaction Window** — The typical timeframe of 5 to 12 days post-vaccination when systemic symptoms like fever and rash may appear due to viral replication.
- **Adverse Event Following Immunization (AEFI)** — Any untoward medical occurrence after immunization, which is not necessarily causally related; ranges from mild, expected reactions to severe events.

## 같은 주제 문제

- [A parent calls the clinic reporting symptoms in their child after a recent MMR vaccine. Wh…](https://mymerci.kr/pages/nclex_q.php?qn_id=541770)
- [A 6-month-old infant received routine immunizations 8 hours ago. The mother calls the clin…](https://mymerci.kr/pages/nclex_q.php?qn_id=541771)
- [A 16-year-old adolescent received routine immunizations 2 hours ago and is now complaining…](https://mymerci.kr/pages/nclex_q.php?qn_id=541772)
- [A 25-year-old adult received the MMR (measles, mumps, rubella) vaccine 8 days ago. The pat…](https://mymerci.kr/pages/nclex_q.php?qn_id=541773)
- [A 2-month-old infant is brought to the pediatric clinic for routine immunizations. The mot…](https://mymerci.kr/pages/nclex_q.php?qn_id=541774)
- [A 6-month-old infant received routine immunizations 2 hours ago and now presents with mild…](https://mymerci.kr/pages/nclex_q.php?qn_id=541775)
- [A 2-year-old toddler presents with a fever of 102°F (38.9°C), vomiting, and lethargy 12 ho…](https://mymerci.kr/pages/nclex_q.php?qn_id=541776)
- [A 2-year-old toddler received routine immunizations 2 hours ago and is now experiencing a …](https://mymerci.kr/pages/nclex_q.php?qn_id=541778)

---

More free questions: [기출문제](https://mymerci.kr/)

_학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요._