Is Your 18-Month-Old's Fever Linked to Recent Vaccinations?

Fever in an 18-month-old toddler?

On Thursday, the child received the second dose of the hepatitis A vaccine and the fourth dose of the pentavalent vaccine.
After the previous vaccinations, there were no fever reactions.
However, on Saturday morning, the child's ear temperature was 38 degrees Celsius, and there were abnormal breath sounds, but no other symptoms.
After rehydration, the child returned to normal activity without any further intervention.
By the afternoon, the ear temperature was 38.5 degrees Celsius.
I would like to know if the fever symptoms could be caused by the vaccines.
Thank you for your response.

zhe, 0~9 year old female. Ask Date: 2022/04/16

Dr. He Zongxian reply Pediatrics

Hello, experiencing a fever two days after receiving an inactivated vaccine is not a typical post-vaccination reaction.
If the fever persists, it is recommended that you take your child to a pediatric medical facility for evaluation, as there may be a risk of urinary tract infection or other pathogenic infections.
Sincerely, He Zongxian, Tainan Municipal Hospital.

Reply Date: 2022/04/16

More Info

When considering whether your 18-month-old's fever is linked to recent vaccinations, it's important to understand the common reactions that can occur after immunizations. Vaccines, including the hepatitis A vaccine and the pentavalent vaccine (which typically includes protection against five diseases), can sometimes cause mild side effects, including fever.
Fever is a common response to vaccinations, as it indicates that the immune system is responding to the vaccine. In the case of the hepatitis A vaccine and the pentavalent vaccine, mild fever can occur in some children. This is generally a normal reaction and usually resolves on its own within a few days. The timing of the fever, occurring shortly after vaccination, supports the possibility that it could be vaccine-related.

In your situation, your child received the second dose of the hepatitis A vaccine and the fourth dose of the pentavalent vaccine on Thursday, and then developed a fever on Saturday. This timeline is consistent with a vaccine-related fever, as it can take a couple of days for the immune response to manifest as a fever. The fact that your child is otherwise active and only has a mild fever (38.5 degrees Celsius) is reassuring.
It's also worth noting that the presence of other symptoms, such as respiratory noise, should be monitored. If your child is experiencing any difficulty breathing, persistent high fever, or any other concerning symptoms, it would be prudent to consult a healthcare provider for further evaluation.
In summary, while it is possible that the fever is related to the recent vaccinations, it is also essential to consider other potential causes, such as viral infections, which are common in young children. If the fever persists or worsens, or if you have any concerns about your child's health, seeking medical advice is always the best course of action.
In addition to monitoring the fever, ensure your child stays hydrated and comfortable. You can use age-appropriate fever reducers, such as acetaminophen, if recommended by your healthcare provider. Always follow the guidance of your pediatrician regarding vaccinations and any subsequent reactions.
In conclusion, while the fever could be a normal response to the vaccinations, it is essential to keep an eye on your child's overall condition and consult with a healthcare professional if you have any concerns. Vaccination is a crucial part of protecting your child's health, and understanding the potential side effects can help you manage them effectively.

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