Study spotlights high incidence of typhoid fever in sub-Saharan Africa

News brief

Tyhpoid outbreak in Africa — Jennifer Murphy / CDC

High incidence of typhoid fever, and the threat of antibiotic-resistant typhoid strains, in sub-Saharan Africa highlight the need for typhoid conjugate vaccines (TCVs), according to a hospital-based surveillance study published this week in The Lancet Global Health.

The 4-year Severe Typhoid in Africa study, led by researchers with the International Vaccine Institute, aimed to address regional gaps in typhoid burden data, characterize levels of antibiotic resistance, and evaluate disease severity in six countries (Burkina Faso, the Democratic Republic of the Congo [DRC], Ethiopia, Ghana, Madagascar, and Nigeria). Researchers enrolled and analyzed data on patients who presented with fever or reported fever for 3 consecutive days within the previous 7 days. Typhoid fever was defined as a febrile illness in which Salmonella enterica serovar Typhi was isolated from blood cultures collected on enrollment.

High incidence, concerning levels of resistance

Of the 27,866 participants recruited from May 2016 through May 2020, blood cultures were performed for 27,544. Clinically significant organisms were detected in 2,136 (7.7%) of blood cultures, with Salmonella Typhi isolated in 346 (16.2%) of 2,055 cultures. Four countries (Burkina Faso, the DRC, Ghana, and Madagascar) had an overall adjusted typhoid incidence of more than 100 cases per 100,000 person-years of observation, with the highest observed in the DRC (315 cases). Rural settings reported the highest incidence.

Of the 346 Salmonella Typhi isolates tested, 172 (57%) of 302 were resistant to ampicillin and 46 (16%) of 280 were showed ciprofloxacin non-susceptibility; the DRC reported the highest prevalence of ciprofloxacin non-susceptibility (24%). Forty-three (16%) of 264 isolates were multidrug-resistant.

The study authors say the increased rates of resistance could eventually render typhoid fever untreatable, and that introduction of TCVs in these countries could contribute substantially to efforts to control typhoid fever.

"Our estimates indicate that introduction of TCV in endemic settings would go to lengths in protecting communities, especially school-aged children, against this potentially deadly—but preventable—disease," lead study author Florian Marks, PhD, deputy director general of the International Vaccine Institute, said in a press release from the institute.

CDC continues to receive reports of MIS-C in kids following COVID infections

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Lisa Schnirring

Cases of multisystem inflammatory syndrome (MIS-C), a rare but serious COVID-19 complication in children, have decreased from the earlier pandemic months but continue to be reported, the Centers for Disease Control and Prevention (CDC) reported today in Morbidity and Mortality Weekly Report (MMWR).

boy in hospital bed — Evgeniy Shkolenko / iStock

The CDC saw a relative increase in MIS-C cases in the fall of 2023, when the United States was experiencing a rise in COVID activity in the general population. Of 117 MIS-C cases reported in 2023, half involved intensive care unit (ICU) care. Of 112 kids with MIS-C who were eligible for immunization with COVID vaccine, 92 (82%) were unvaccinated. And, of 20 vaccinated children, 60% had waned immunity at the time of their MIS-C illness.

"COVID-19 vaccination remains important for preventing MIS-C," the CDC said. Incidence of the condition peaked in late 2020 and early 2021. The condition typically occurs 2 to 6 weeks after COVID infection.

MIS-C causes different body parts to become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, and gastrointestinal tract. Though the condition can be serious or fatal, most children recover after medical care.

Study: Men with key anti-inflammatory genetic variant almost 80% less likely to die of COVID

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Mary Van Beusekom, MS

COVID inflammation — *ALIOUI Mohammed Elamine / iStock*

Hospitalized male COVID-19 patients younger than 75 who have a certain variant of a key anti-inflammatory gene are at much lower risk of experiencing severe inflammation and dying of the disease, New York University researchers reported yesterday in The Journal of Infectious Diseases.

The team obtained blood samples from 2,589 hospitalized COVID-19 patients to examine the link between single-nucleotide variants of the interleukin-1 receptor antagonist (IL1RN), markers of inflammation and death from March 2020 to March 2021.

Of the 2,589 patients, 124 men (4.8%) had the protective rs419598 IL1RN variant. More than half of the patients were older than 60 years and obese, factors that raise the risk of COVID-19 death.

Significantly lower inflammatory marker levels

The overall death rate was 15.3%. More men than women (240 men [60.5% of all deaths] and 157 women [39.5%]) died of COVID-19, with women 24% less likely to die than men (13.1% vs 17.3%).

Our analysis offers substantial evidence of the biological link between the severe inflammation seen in SARS-CoV-2 and that which occurs in rheumatoid arthritis.

Steven Abramson, MD

Men with rs419598 had significantly lower inflammatory biomarker concentrations and a lower death rate than those with another studied genotype (10.0% vs 17.8%). The most pronounced association was seen in men younger than 75 years, who had a 78% lower death rate (3.1% vs 14.0%).

"Our analysis offers substantial evidence of the biological link between the severe inflammation seen in SARS-CoV-2 and that which occurs in rheumatoid arthritis," senior author Steven Abramson, MD, said in an NYU news release. He added that previous research has shown that rheumatoid inflammation is lower in patients who have one of the three studied IL1RN variants.

Tamping down the interleukin-1 biologic pathway, which is partially accomplished by the anti-inflammatory protein IL-1Ra, may help prevent severe COVID-related inflammation. The authors called for future research on whether IL 1–inhibiting therapies like the IL1 receptor antagonists anakinra, canakinumab, and rilonacept, are effective against COVID-19.

Data show global declines in TB incidence, deaths in young people

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Chris Dall, MA

Global tuberculosis (TB) incidence, mortality, and disability-adjusted life years (DALYs) have decreased significantly in adolescents and young adults since 1990, but the incidence of drug-resistant TB increased, Chinese researchers reported today in Pediatrics.

Using data from the Global Burden of Disease Study 2019, researchers from Peking University and Tsinghua University calculated the percentage of relative changes in TB incidence, deaths, and DALYs in people aged 10 to 24 from 1990 to 2019. They assessed temporal changes using estimated annual percentage changes (EAPCs).

Globally, the number of incident TB cases in adolescents fell from 2.23 million in 1990 to 1.82 million in 2019, while the number of TB deaths fell from 0.11 million to 0.6 million . The number of DALYs declined from 8.74 million to 4.87 million. Incidence, deaths, and DALYs per 100,000 population saw relative declines of 32.3%, 56.6%, and 53.7%, respectively, with EAPCs of 1.28%, 3.06%, and 2.83%.

Similar decreasing trends occurred across sex, age, sociodemographic index regions, and in most regions and countries. But TB incidence decreased faster in female adolescents than male, and increases in incidence were observed in sub-Saharan African countries, with the largest seen in South Africa (EAPC, 3.51).

Increases in drug-resistant TB

In contrast to those trends, the incidence of extensively drug-resistant TB rose 11.2% each year, and multidrug-resistant TB without extensive resistance climbed 3.3% each year.

The study authors say the declines are primarily because of increased investment in TB prevention and control, along with improvements in TB diagnosis and treatment. Increased incidence of drug-resistant TB, meanwhile, is likely from advances in detection technology and drug-susceptibility testing. But they note that the actual incidence of drug-resistant TB may be underestimated, since data from the World Health Organization Global Tuberculosis Program has shown that only one third of people with drug-resistant TB are detected worldwide.

"TB remains a concern in adolescents and young adults, especially in low- and middle-income countries," they wrote. "Thus, efforts to reduce the incidence and mortality of TB in adolescents and young adults are essential worldwide."