Invasive Group A Strep (iGAS) in Babies - Post-COVID Surge
Content reviewed against published CDC, AAP, NIH guidelines
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If your baby has been diagnosed with or you suspect invasive group a strep (igas) in babies - post-covid surge, here is what the evidence says.
The short answer
Invasive Group A Streptococcus (iGAS) infections in young children surged 7x above pre-pandemic levels after COVID restrictions were lifted, likely due to an "immunity gap" from reduced pathogen exposure during lockdowns. While most Group A Strep infections (like strep throat or impetigo) are mild and treatable with antibiotics, invasive disease can cause pneumonia, bone and joint infections, sepsis, and necrotizing fasciitis. Babies under 1 year are especially vulnerable. Early antibiotic treatment is critical.
Key takeaways
- Invasive Group A Streptococcus (iGAS) infections in young children surged 7x above pre-pandemic levels after COVID restrictions were lifted, likely due to an "immunity gap" from reduced pathogen exposure during lockdowns. While most Group A Strep infections (like strep throat or impetigo) are mild and treatable with antibiotics, invasive disease can cause pneumonia, bone and joint infections, sepsis, and necrotizing fasciitis. Babies under 1 year are especially vulnerable. Early antibiotic treatment is critical.
- Usually normal when: Your child has mild strep throat or impetigo and is improving with prescribed antibiotics.
- Call your doctor if: Your baby under 3 months has a fever of 100.4F (38C) or higher - this always needs immediate evaluation.
- Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
Parents everywhere have the same worry. You are doing the right thing by looking into it.
When to Seek Immediate Care
- Your baby under 3 months has a fever of 100.4F (38C) or higher - this always needs immediate evaluation.
- Your child has a rapidly spreading area of redness, swelling, or skin that looks infected and is growing over hours.
- Your child has a high fever and appears very unwell - unusually lethargic, inconsolable, or difficult to rouse.
- Your child has a fever and severe pain in a limb, refuses to move an arm or leg, or is limping and getting worse.
- Your child with strep throat or scarlet fever is deteriorating despite being on antibiotics.
By Age
What to expect by age
0-3 months
Newborns can acquire Group A Strep during or after delivery. In young infants, iGAS may present as fever, poor feeding, irritability, lethargy, or a rapidly worsening skin infection. Because newborns cannot localize infections well, what starts as a mild-looking skin rash can progress to bloodstream infection quickly. Any fever (100.4F/38C or higher) in a baby under 3 months requires immediate medical evaluation regardless of suspected cause.
3-12 months
Babies in this age group may develop iGAS from skin wounds, chickenpox lesions (which allow bacteria entry), or respiratory exposure from family members with strep throat. Symptoms of invasive disease include: high fever that does not respond well to medication, a rapidly spreading red or swollen area on the skin, refusal to use a limb (suggesting bone or joint infection), rapid breathing, and appearing very unwell. If your baby has a skin infection that is spreading despite treatment, or develops a high fever with any of these symptoms, seek emergency care.
12-36 months
Toddlers are increasingly exposed to Group A Strep through daycare and social settings. Most infections at this age are superficial (strep throat, impetigo, scarlet fever) and respond well to oral antibiotics. However, if your toddler has scarlet fever or strep throat and is getting worse despite 48 hours of antibiotics, or develops new symptoms like severe pain in an arm or leg, spreading redness, swelling, or difficulty breathing, seek urgent evaluation. The post-pandemic strains (particularly emm1) have been associated with more severe outcomes in young children.
What Should You Do?
When to take action
- Your child has mild strep throat or impetigo and is improving with prescribed antibiotics.
- Your child has scarlet fever (strep throat with a sandpaper rash) and is responding to antibiotic treatment.
- Your child was exposed to someone with strep but has no symptoms.
- Your child has a skin infection that does not seem to be improving after 48 hours of prescribed antibiotics.
- Your child keeps getting recurrent strep infections.
- Someone in your household has strep throat and you want to know how to protect your baby.
- Your baby under 3 months has a fever of 100.4F (38C) or higher - this always needs immediate evaluation.
- Your child has a rapidly spreading area of redness, swelling, or skin that looks infected and is growing over hours.
- Your child has a high fever and appears very unwell - unusually lethargic, inconsolable, or difficult to rouse.
- Your child has a fever and severe pain in a limb, refuses to move an arm or leg, or is limping and getting worse.
- Your child with strep throat or scarlet fever is deteriorating despite being on antibiotics.
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Invasive Group A Strep (iGAS) in Babies - Post-COVID Surge.
Things to mention
- Your child has a skin infection that does not seem to be improving after 48 hours of prescribed antibiotics.
- Your child keeps getting recurrent strep infections.
- Someone in your household has strep throat and you want to know how to protect your baby.
Observations to share
- Your child has a skin infection that does not seem to be improving after 48 hours of prescribed antibiotics.
- Your child keeps getting recurrent strep infections.
- Someone in your household has strep throat and you want to know how to protect your baby.
Urgent signs to report immediately
- Your baby under 3 months has a fever of 100.4F (38C) or higher - this always needs immediate evaluation.
- Your child has a rapidly spreading area of redness, swelling, or skin that looks infected and is growing over hours.
- Your child has a high fever and appears very unwell - unusually lethargic, inconsolable, or difficult to rouse.
My notes
From ismybabyalright.com — free, evidence-based baby health guides
Related Conditions
Strep Throat in Baby or Toddler
Strep throat (Group A Streptococcus infection) is uncommon in babies under 2 years but can occur in toddlers. It is most common in children ages 5-15. In toddlers, strep may present differently than in older children - instead of the classic sore throat, toddlers may have low-grade fever, irritability, decreased appetite, runny nose, and swollen lymph nodes. A rapid strep test or throat culture is needed for diagnosis. Strep throat requires antibiotic treatment (usually amoxicillin for 10 days) to prevent complications including rheumatic fever.
baby first fever
When to Call Your Pediatrician
Knowing when to call your pediatrician can be stressful, but a good rule of thumb is: if something about your baby worries you, it is always okay to call. In general, any fever in a baby under 3 months, difficulty breathing, signs of dehydration, or a sudden change in behavior warrants a prompt call. Trust your instincts - you know your baby best, and pediatricians expect and welcome these calls.
baby skin infection cellulitis
Related Resources
Fever Decision Tree
Step-by-step guidance for evaluating your baby's fever by age and temperature.
Month-by-Month Development
Detailed monthly development guides from birth through 24 months.
When to Call the Doctor
General guide on when to call the pediatrician, visit urgent care, or go to the ER.
Frequently asked questions
Is invasive group a strep (igas) in babies - post-covid surge normal?
When should I call the doctor about invasive group a strep (igas) in babies - post-covid surge?
When is invasive group a strep (igas) in babies - post-covid surge normal?
What causes invasive group a strep (igas) in babies - post-covid surge?
What should I mention to my pediatrician about invasive group a strep (igas) in babies - post-covid surge?
Is invasive group a strep (igas) in babies - post-covid surge normal at 0-3 months?
Is invasive group a strep (igas) in babies - post-covid surge normal at 3-12 months?
Should I go to the ER for invasive group a strep (igas) in babies - post-covid surge?
Does invasive group a strep (igas) in babies - post-covid surge go away on its own?
References
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Resources
Bottom line
Most cases of invasive group a strep (igas) in babies - post-covid surge are normal. Talk to your pediatrician if your baby under 3 months has a fever of 100.4f (38c) or higher - this always needs immediate evaluation.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Medical Concerns
Strep Throat in Baby or Toddler
Strep throat (Group A Streptococcus infection) is uncommon in babies under 2 years but can occur in toddlers. It is most common in children ages 5-15. In toddlers, strep may present differently than in older children - instead of the classic sore throat, toddlers may have low-grade fever, irritability, decreased appetite, runny nose, and swollen lymph nodes. A rapid strep test or throat culture is needed for diagnosis. Strep throat requires antibiotic treatment (usually amoxicillin for 10 days) to prevent complications including rheumatic fever.
When to Call Your Pediatrician
Knowing when to call your pediatrician can be stressful, but a good rule of thumb is: if something about your baby worries you, it is always okay to call. In general, any fever in a baby under 3 months, difficulty breathing, signs of dehydration, or a sudden change in behavior warrants a prompt call. Trust your instincts - you know your baby best, and pediatricians expect and welcome these calls.
My Baby Has Impetigo
Impetigo is a common bacterial skin infection in babies and young children, caused by staph or strep bacteria. It appears as red sores that quickly develop into honey-colored crusts, most often around the nose, mouth, and hands. While it looks unpleasant, impetigo is very treatable with antibiotic ointment or oral antibiotics and clears up within a week or two of starting treatment.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.