In 2011, scarlet fever began to surge in China and continued to occur at an increased incidence for 6 consecutive years, according to findings published in The Lancet Infectious Diseases.
Researchers reviewed governmental epidemiological data for all scarlet fever cases in China from 2004 to 2016 and used modeling to examine the patterns and annual percentage change in incidence of the disease across the country.
Between Jan. 1, 2004, and Dec. 31, 2016, there were 502,723 reported cases of scarlet fever, including 10 fatalities — an annualized average incidence of 2.8807 cases per 100,000 people, according to the researchers. The incidence was 1.457 cases per 100,000 people in 2004 and surged to 4.7638 per 100,000 people in 2011.
Following the 2011 increase, there continued to be an above-average annual incidence of scarlet fever, except for 2013. The incidence peaked in 2015 (5.0092 per 100,000 people) and then decreased in 2016 (4.3247 per 100,000 people). From 2011 to 2016, the average annual incidence was twice that of the period from 2004 to 2010 (4.0125 vs. 1.9105 per 100,000 people; incidence rate ratio (IRR) = 2.07; 95% CI, 2.06-2.09; P < .0001).
“The reasons for this increase could include microbial, host, and meteorological factors,” the researchers wrote.
The median age of scarlet fever onset was 6 years and ranged from 4 days to 83 years, the researchers reported. Children aged 6 years had the highest average annual incidence (49.4675 per 100,000 people) and adults aged 80 to 85 years had the lowest average annual incidence (0.0096 per 100,000 people).
In an analysis of reported scarlet fever cases by age and sex, the annual incidence was higher among men and boys than among women and girls in all age groups. Peaks were observed in 2011 and 2015 in the annual incidence of scarlet fever in patients aged 0 to 2 years and 3 to 6 years, whereas the incidence in children aged 7 to 14 years peaked at three time points: 2007, 2011 and 2015, the researchers noted.
In a related editorial, Xingyu Zhang, PhD, of the department of surgery at Emory University School of Medicine, and Yan-Cun Liu, MD, from the department of emergency medicine at Tianjin Medical University General Hospital in China, emphasized the importance of closer monitoring of scarlet fever in China.
“Given the resurgence of scarlet fever, surveillance systems should be strengthened both in China and other countries, especially since no vaccine exists for scarlet fever,” they wrote. “Although several M-protein based vaccines have progressed to human clinical trials, none have moved beyond phase 2 trials.” – by Jennifer Byrne
The researchers report no relevant disclosures.