Weekly Digest: CDDEP study on mortality associated with poor-quality antimalarials, Malaria vaccine trials

Poor-quality antimalarial drugs may have been responsible for as many as 122,000 deaths of children under five in sub-Saharan Africa in 2013, according to a study by CDDEP researchers in a special World Malaria Day (April 25) issue of the American Journal of Tropical Medicine and Hygiene that focused on falsified and substandard drugs. [American Journal of Tropical Medicine and Hygiene]

The final results of a phase three trial of the RTS,S/AS01 malaria vaccine—including the effect of a booster dose—were published in The Lancet this week. In addition to the protection offered by the initial three-dose series (reported on previously), a booster at 20 months offered some extra protection for up to four years. According to vaccine expert Adrian Hill, despite progress in making a vaccine with limited efficacy—vaccine efficacy in 5-17 month olds was about 32 percent with a booster—“its potential public health benefits and utility is not yet clear.” [The Lancet, The Guardian]

Antibiotic resistance was found in a remote Amazonian tribe that has never been exposed to antibiotics. A study in Science Advances reported on the microbiomes of Yanomami tribespeople, who had no documented previous contact with Westerners. The study found the Yanomami “harbor a microbiome with the highest diversity of bacteria and genetic functions ever reported in a human group,” including bacteria with a variety of antibiotic-resistance genes. The authors say this shows that bacteria evolved the ability to fight toxins earlier than previously thought. [Science Advances, Science News]

Up to 10,000 additional malaria deaths may occur as a result of the West African Ebola outbreak due to decreased health care capacity, according to a study published in The Lancet. The World Health Organization published a statement last week that admitted to numerous faults in its response to the outbreak and detailed steps that it will take to improve future responses. [The Lancet, WHO]

The U.S. has experienced shortages of over a hundred antibiotics since 2001. A paper written by researchers at George Washington University found evidence of shortages of 148 antibacterial drugs between 2001 and 2013, with a notable increase after mid-2007, which they attributed to the recession. Nearly half of the shortages were antibiotics for “high-risk” pathogens, such as MRSA and Pseudomonas aeruginosa. [Clinical Infectious Diseases]

The CDC confirmed that products from Blue Bell Creameries caused an outbreak of listeriosis in the United States. The ice cream manufacturer voluntarily recalled all of its products after 10 cases and 4 deaths had been reported across four states. Epidemiologists connected the dots by using whole genome sequencing to trace different strains back to patients who had been exposed up to five years ago. [NPR, CDC]

Resistance to antimalarial drug artemisinin may be tied to a strong stress response from the malaria parasite. Research published in PLOS Biology reported on the mechanism of artemisinin against malaria parasites: the drug damages the parasite’s proteins and activates a cellular stress response. When the stress response is particularly vigorous, however, the drug is rendered ineffective, though longer regimens can overcome the effect of the stress response. Another study published this week confirmed artemisinin resistance for the first time in Africa. [PLOS Biology, Antimicrobial Agents and Chemotherapy]ˇ

Pilgrim’s Pride Corp., America’s second-largest poultry processor, announced that it will cut its use of all antibiotics in chicken products by 25 percent. The reduction plan will be rolled out through the end of 2018 and also includes reducing use of medically important antibiotics. [The Wall Street Journal]

The measles outbreak that began at Disneyland last December has been declared over, with no cases reported in California for 42 days. Heated debates on mandatory vaccination in the California continued this week as a bill that would end vaccine exemptions passed the state’s Senate Education Committee. A large study published Tuesday in the Journal of the American Medical Association found “no harmful association between MMR vaccine receipt and ASD [autism spectrum disorders] even among children already at higher risk for ASD”.  [The Washington Post, The New York Times, JAMA]

NIH awarded a grant for a rapid diagnostic device that would detect antibiotic-resistant bacteria and recommend an appropriate antibiotic. The ideal device would shorten the time it takes to diagnose infections from up to three days to about three hours, select an appropriate antibiotic and “pinpoint the precise drug dosage needed to inflict a fatal blow.” Hellen Gelband’s recent CDDEP blogpost takes the quest further, to “smart” antibiotics. [Infection Control Today, CDDEP]