Vaccine Side Effects in Infants: What New Parents Should Know - Pediatrics

Share to:

Vaccine side effects


Hello doctor, my baby (2 months and 18 days old) received the pentavalent vaccine on Saturday the 29th.
On Sunday the 30th, I noticed a lump and redness at the injection site.
Today, the 10th, he has a slight fever.
Is this a side effect of the vaccine? How long is it likely to last? As a new mom, I'm quite anxious and worried!

Meng Ting, 20~29 year old female. Ask Date: 2018/10/10

Dr. Xiao Kaiwen reply Pediatrics


If the pentavalent vaccine causes a fever, it typically occurs within 24 hours after administration.
Since your child developed a fever 10 days later, this fever is likely not a side effect of the vaccine.
Please closely monitor the fever and activity level.
If the fever becomes more pronounced or if there is a decrease in activity, please go to a major hospital's pediatric emergency department for evaluation, as infants under 3 months of age with a fever require more detailed examination and possibly hospitalization.

Reply Date: 2018/10/10

More Info


When it comes to vaccinations for infants, it's completely normal for new parents to feel anxious about potential side effects. Vaccines are crucial for protecting children from serious diseases, but they can also cause mild reactions. In your case, your baby received the pentavalent vaccine (5-in-1), which is designed to protect against several diseases, including diphtheria, tetanus, pertussis (whooping cough), polio, and Haemophilus influenzae type b (Hib).

After vaccination, it is common for infants to experience some localized reactions at the injection site. This can include redness, swelling, and the formation of a hard lump, which are all typical responses to the vaccine. These reactions are usually mild and resolve on their own within a few days. The redness and swelling indicate that the body is responding to the vaccine, which is a sign that the immune system is working to build protection against the diseases.

As for the mild fever you observed, it is also a common side effect following vaccinations. Fever is a natural response of the immune system as it reacts to the vaccine. Generally, this fever should not last more than a couple of days. If the fever persists beyond 48 hours or reaches a high temperature (over 102°F or 39°C), it would be advisable to consult your pediatrician for further evaluation.

In terms of managing these side effects, you can help your baby feel more comfortable. For localized reactions, applying a cool compress to the injection site can help reduce swelling and discomfort. If your baby has a fever, you may consider using age-appropriate fever reducers, such as acetaminophen, but always consult your pediatrician before administering any medication.

It's important to note that while side effects can be concerning, they are generally mild compared to the potential severity of the diseases that vaccines prevent. Vaccination is a critical step in ensuring your child's health and well-being. The benefits of vaccination far outweigh the risks of mild side effects.

As a new parent, it's natural to worry, but keeping an open line of communication with your healthcare provider can help alleviate concerns. They can provide guidance tailored to your child's specific health needs and reassure you about what to expect after vaccinations. If you notice any unusual symptoms, such as a rash, difficulty breathing, or persistent crying, seek medical attention immediately, as these could be signs of a more serious reaction, although such occurrences are extremely rare.

In summary, localized reactions and mild fever following vaccinations are common and typically resolve within a few days. Monitoring your child's symptoms and maintaining communication with your healthcare provider will help ensure that any concerns are addressed promptly. Remember, vaccinations are a vital part of your child's health journey, providing protection against potentially serious illnesses.

Similar Q&A

Concerns About Vaccine Errors in Infants: What Parents Should Know

My daughter is currently over 9 months old. She was taken to receive the measles vaccine but was instead administered the measles, mumps, and rubella (MMR) vaccine, which is typically given at 12 to 15 months of age, along with the first dose of the Japanese encephalitis vaccine....


Dr. Zhao Yongkang reply Pediatrics
Dear Ms. Ivy, 1. Please have the physician check for any other symptoms of infection. 2. Generally speaking, if the vaccination schedule is not followed correctly and the child does not exhibit any specific symptoms, there should be no major issues, but observation is still nece...

[Read More] Concerns About Vaccine Errors in Infants: What Parents Should Know


Can Flu Vaccine Cause Rashes in Infants? Understanding Pediatric Reactions

Hello Doctor, my baby was born on April 19, 2007. After reaching six months, on October 30, 2007, he received the first dose of the influenza vaccine (from Pasteur) and the third dose of the pneumococcal vaccine in the afternoon. However, there were no obvious symptoms after the ...


Dr. Pei Rensheng reply Pediatrics
Hello: The most common side effects of the influenza vaccine are localized pain and swelling at the injection site. There are also rare occurrences of systemic reactions, such as fever, myalgia, and fatigue. Allergic and neurological reactions are infrequent. According to a surve...

[Read More] Can Flu Vaccine Cause Rashes in Infants? Understanding Pediatric Reactions


Concerns After 5-in-1 Vaccine: What Parents Should Know

My baby is now two months old, and when I took him to get the DTaP-Hib-IPV-HepB (5-in-1) vaccine, the nurse administered it. Afterward, while preparing to give the oral Sabin vaccine, I reminded her that it was the 5-in-1 vaccine that was given. She responded that the 5-in-1 vacc...


Dr. Liang Hongjian reply Pediatrics
Hello: Every type of vaccine carries varying degrees of risk. The likelihood of developing complications from Japanese encephalitis after receiving the vaccine, according to the literature, is very low. Currently, your situation involves an excessive amount of vaccine, which may ...

[Read More] Concerns After 5-in-1 Vaccine: What Parents Should Know


Concerns About Vaccination Reactions in Young Children: A Parent's Dilemma

Dr. Lin: Hello, my child turned one and a half years old on the 15th of this month and needed to receive the diphtheria, tetanus, and pertussis (DTaP) combination vaccine. He had previously received the pentavalent vaccine for his first three doses, but when I took him to the hos...


Dr. Lin Huizhen reply Pediatrics
Dear Mother of the Child, I hope this message finds you well. I wanted to check in to see if your child’s fever has subsided and how their overall condition is. It is important to note that the likelihood of developing a fever from the pentavalent vaccine is similar to that of...

[Read More] Concerns About Vaccination Reactions in Young Children: A Parent's Dilemma


Related FAQ

Vaccine

(Pediatrics)

Enterovirus

(Pediatrics)

Purpura

(Pediatrics)

Infant Urination

(Pediatrics)

Nasal Allergy

(Pediatrics)

Cough

(Pediatrics)

Fever

(Pediatrics)

Breastfeeding

(Pediatrics)

Kidney

(Pediatrics)

Pediatric Vomiting

(Pediatrics)