A study conducted in Europe found that Salmonella has become the leading cause of invasive bacterial infection (IBI) in children with sickle cell disease (SCD), researchers reported yesterday in Pediatrics.

For the study, a team of European researchers analyzed data from 28 pediatric hospitals in five European countries on children with SCD who had IBI episodes from 2014 through 2019. Children with SCD have a higher risk of IBI, and prior to the widespread use of 13-valent pneumococcal conjugate vaccines (PCV13), Streptococcus pneumoniae had been the leading cause of IBI in children with the disease. The aim of the study was to evaluate the causes of IBI post-PCV13 implementation.

The researchers analyzed data on 169 IBI episodes in 156 children (51% girls, median age 7.8 years); 85 of 138 children (62%) had completed PCV13 vaccination. Among the 169 episodes, Salmonella spp. was the main isolated bacteria (44 cases, 26%), followed by S pneumonia (31, 18%) and Staphylococcus aureus (20, 12%). Salmonella was mainly found in osteoarticular infections and in primary bacteremia (45% and 23% of episodes, respectively) and S pneumoniae in meningitis and acute chest syndrome (88% and 50%, respectively).

All S pneumoniae IBI occurred in children under 10 years, including 35% in children 5 to 10 years old. The outcomes were favorable in 129 cases (81%), but 27 (17%) children had complications of infection and three died: two because of S pneumoniae, and one because of Salmonella. The main risk factors for a severe infection were a previous IBI and pneumococcal infection.

A shift in the epidemiology

The authors say this is the first time in a study in high-income countries that S pneumoniae was not the most common cause of IBI in children with SCD, a finding they say suggests a shift in the epidemiology in the post-PCV13 era.

"Although a major goal in children with SCD should be the prevention of Sp [S pneumoniae] infection, IBI due to Salmonella is an emerging problem," they wrote. "Effective preventive and treatment strategies should be developed, including broader valent pneumococcal vaccines."

The UK government yesterday announced an award of £1.4 million ($1.7 million) to accelerate the development of vaccines to combat antimicrobial resistance (AMR).

The award from the government's Global AMR Innovation Fund (GAMRIF) will help the University of Birmingham-hosted Bacterial Vaccines Network (BactiVac) diversify its pipeline of bacterial vaccine development projects. BactiVac was founded in 2017 to advance the development of vaccines targeting the bacterial pathogens of global importance.

In a July 2022 report, the World Health Organization said that with the current antibiotic pipeline relatively short on new candidates, vaccines have become a "highly attractive" tool that could help curb AMR by reducing the incidence of bacterial infections and reducing the overall use and misuse of antibiotics.

"GAMRIF supports strategies to tackle AMR and bacterial vaccines play a key role in this by preventing bacterial diseases from developing, removing the need to use antimicrobials and reduce opportunities for AMR to develop," BactiVac co-director Adam Cunningham, PhD, said in a news release. "This is a key reason why the partnership between GAMRIF and BactiVac is so important for controlling AMR."

BactiVac brings together more than 1,400 academic, industry, and policy partners from the United Kingdom and 78 other countries, over half of which are low- and middle-income countries. It's pipeline of projects includes vaccines that target bacterial infections in animals as well as humans.

• In a technical report today, the European Centre for Disease Prevention and Control (ECDC) proposed a plan for increasing testing for human avian influenza infections in areas experiencing outbreaks in animals in a way that doesn't overburden the health system. Steps include asking people admitted to the hospital for respiratory diseases about recent exposure to sick or dead birds or animals and testing hospitalized people who have unexplained viral illnesses, especially those who have neurologic symptoms. The ECDC also proposed testing for seasonal and avian flu when clusters of patients are hospitalized if routine testing is inconclusive and noted that wastewater surveillance is another option for affected areas.
• Sudan has declared a cholera outbreak in Gedaref state that has sickened 264 people and led to 14 deaths, the World Health Organization (WHO) said today. Investigations are under way into spread of the disease to Khartoum and South Kordofan states. The group said it is scaling up its response and had already sent cholera supplies to six Sudan states, and plans are under way to obtain oral cholera vaccine. Sudan is experiencing war between rival factions of the military government and is grappling with population displacement, disease outbreaks, and malnutrition, all made worse by heavy rains and flooding. Last week, the WHO said cholera cases more than doubled in 2022 and continue to climb in 2023, with at least 24 countries currently reporting active outbreaks.
• Four countries reported more polio cases this week, all involving vaccine-derived types, the Global Polio Eradication Initiative (GPEI) said in its latest update. Ivory Coast reported one circulating vaccine-derived poliovirus type 2 (cVDPV2) case, bringing its total for the year to three. The Democratic Republic of the Congo (DRC) reported eight cVDPV2 cases, along with two cases involving circulating vaccine-derived poliovirus type 1 (cVDPV1), lifting its annual totals to 89 and 61, respectively. Elsewhere, Madagascar reported four cVDPV1 cases, putting its total at 17 for the year, and Mali reported two cVDPV2 cases, making eight for 2023.