Group A Streptococcus cases spike following decline during COVID-19 pandemic

Group A Streptococcus cases spike following decline during COVID-19 pandemic | Image Credit: © kerkezz Doe - © kerkezz - stock.adobe.com.

As the COVID-19 pandemic draws to a close, the Centers for Disease Control and Prevention (CDC) warn that this is not a time to be complacent. Many different types of infectious diseases saw a drop in cases during the pandemic because of limited socialization and increased infection control measures. But now that the pandemic is less a part of our daily lives, it appears that at least some types of infections are returning to baseline—and then some.

According to the CDC, historic declines in invasive group A Streptococcus (iGAS) infections were reported during the COVID-19 pandemic, but by fall 2022, the agency was tracking a resurgence. This resurgence, reported by the CDC in the March issue of Morbidity and Mortality Weekly Report (MMWR), was highlighted by data from 2 of the agency’s 10 Emerging Infections Program surveillance sites.¹

Group A Streptococcus cases increased in all age groups, according to the CDC, but increases in children and teenagers were notable for developing outside normal seasonal patterns, according to Jane M. Carnazzo, MD, FAAP. Carnazzo is a pediatrician at Children’s Hospital & Medical Center in Omaha, Nebraska, who serves on the American Academy of Pediatrics (AAP) Section of Infectious Diseases, and an editorial advisory board member of this journal.

“It’s been a crazy year. This is the greatest number of strep cases in the past 5 years following an all-time low in 1997,” Carnazzo says. “Strep is a little seasonal, with a lot more cases in the spring and fall. But just like with COVID, when there is nothing else circulating, there are other things that can kick up.”

This seems to be the case with group A Streptococcus in fall 2022, when Streptococcus infections peaked earlier than usual. From October to December 2022, 34 cases of iGAS were recorded at surveillance sites in Colorado and Minnesota. In comparison, the 3-month average was 11 cases from 2016 to 2019 and only 4 cases between 2020 and 2021. Additionally, these cases were seen most commonly in younger children, with a median age of 3.1 years in the Colorado cases compared with the 5- to 6-year range seen before and during the COVID-19 pandemic. Additionally, 2 deaths were recorded at the Colorado and Minnesota surveillance sites in 2022, whereas 5 deaths were recorded in the previous 5-year period from 2016 to 2021.¹ The World Health Organization reported a similar rise in iGAS disease and cases of scarlet fever in late 2022.²

What didn’t seem to increase, however, was frequency of intensive care unit admission or length of hospital stays associated with these iGAS cases, which remained similar to prepandemic baselines. Additionally, many of the children who developed iGAS during the increase period had underlying medical conditions that may have increased their overall risk of infection.

The spike in iGAS cases wasn’t just earlier than usual, Carnazzo notes, but also linked up closely with spikes in other viral respiratory illnesses. According to the CDC, approximately 62% of cases recorded in MMWR were associated with an upper respiratory tract infection about 2 weeks prior to the Streptococcus diagnosis. Additionally, 18% of patients reported a sore throat in the period before their diagnosis, and 20.6% reported having no other illness before iGAS. Nearly half of patients who attained a positive test result for iGAS also attained a positive result for 1 or more viral illnesses in the 2 weeks prior to or at the same time as the Streptococcus infection. Respiratory syncytial virus and influenza A virus were most common, followed by COVID-19. In pediatric cases, concurrent viral illness with group A Streptococcus infection appeared to increase disease severity and hospitalization rates.¹

Although group A Streptococcus is highly contagious and linked to a number of diseases, Carnazzo says rheumatic fever is usually the main complication to avoid in the pediatric population.³ Resistance to iGAS usually develops with age but becomes less common in adulthood, she adds.

Antimicrobial resistance is another concern, with antibiotic-resistant strains of many bacterial illnesses emerging in the years before the pandemic. However, Streptococcus is not one of those illnesses, Carnazzo explains. The CDC adds that the majority of cases observed during the current spike were susceptible to all antimicrobials. One isolate was resistant to erythromycin, and 2 were resistant to erythromycin plus clindamycin and tetracycline, the CDC reports.³ Outside of colonization and the building of natural immunity, there is no vaccine for group A Streptococcus, but the CDC points out that keeping vaccinations up-to-date against other viral respiratory illnesses can help head off severe or concurrent infection with iGAS.³ Appropriate testing and treatment are also important, Carnazzo says.“ Infectious disease experts will tell you that if [patients] have a cough, runny nose, and fever, it’s not always a good idea to test for strep,” she says, explaining that these symptoms usually signal other upper respiratory infections. Individuals who attain a positive test result for iGAS with these symptoms may not be actively infected but experiencing germ colonization instead, she warns. “Test the kids who should be tested, and be careful whom you test to avoid getting a positive [result from] those kids [with germ colonization],” Carnazzo says.

Decreased masking and the relaxation of other infection control methods in the aftermath of the COVID-19 pandemic—along with the closure of schools for long periods of time—likely contributed to the initial drop and following surge in iGAS, Carnazzo says. Moving forward, judicious testing⁴ and effective treatment are key, she says, adding that antibiotics in the penicillin class (amoxicillin) are the first choice, followed by cephalosporins (cefalexin).

Carnazzo also suggests using the AAP’s Red Book: 2021-2024 Report of the Committee on Infectious Diseases⁵ for guidance on testing. Parents should also be educated on the value of infection prevention measures from the COVID-19 era to help reduce iGAS risk. This includes concepts such as strict hand hygiene, masking, and avoiding individuals who are sick.⁶

For more from the July, 2023 issue of Contemporary Pediatrics®, click here.

References:

1. Barnes M, Youngkin E, Zipprich J, et al. Notes from the field: increase in pediatric invasive group A Streptococcus infections - Colorado and Minnesota, October-December 2022. MMWR Morb Mortal Wkly Rep. 2023;72(10):265-267. doi:10.15585/mmwr.mm7210a4

2. Increased incidence of scarlet fever and invasive group A Streptococcus infection - multi-country. World Health Organization. December 15, 2022. Accessed May 31, 2023. https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON429

3. Diseases caused by group A strep. Centers for Disease Control and Prevention. Updated June 27, 2022. Accessed June 2, 2023. https://www.cdc.gov/groupastrep/diseases-public/index.html

4. Norton LE, Lee BR, Harte L, et al. Improving guideline-based streptococcal pharyngitis testing: a quality improvement initiative. Pediatrics. 2018;142(1):e20172033. doi:10.1542/peds.2017-2033

5. Group A streptococcal infections. In: American Academy of Pediatrics. Red Book: 2021-2024 Report of the Committee on Infectious Diseases. 32nd ed. American Academy of Pediatrics; 2021. Accessed June 13, 2023. https://publications.aap.org/redbook/book/347/chapter-abstract/5756422/Group-A-Streptococcal-Infections?redirectedFrom=fulltext

6. Increase in invasive group A strep infections, 2022-2023. Centers for Disease Control and Prevention. Updated February 2, 2023. Accessed June 3, 2023. https://www.cdc.gov/groupastrep/igas-infections-investigation.html