Three Rounds of Antibiotic Therapy Superior to Targeted Treatment for Reducing Yaws Cases

By Gene Emery

January 06, 2022

(Reuters Health) - As a strategy for halting the spread of yaws, mass administration of three rounds of azithromycin at six-month intervals was four times more effective than a single round followed by two rounds of targeted treatment, according to results from more than 56,000 children in Papua New Guinea.

The World Health Organization is trying to eradicate the disfiguring skin and long-bones infection by 2030.

"Our intervention led to a tremendous reduction in the prevalence of the disease," team leader Dr. Oriol Mitja told Reuters Health in an email.

The cluster-randomized trial, reported in The New England Journal of Medicine, was undertaken out of concern that the current strategy that includes targeted treatment, "which focuses only on persons with active infection and their contacts, may not achieve a sufficient level of treatment coverage among those with latent infection," said the team.

They used one of the two strategies in 38 regions.

Before treatment, the prevalence of active yaws was 0.43% in the group where everyone was destined to get three treatments and 0.46% with conventional therapy.

After 18 months, the rates were 0.04% and 0.16% respectively.

The researchers estimated that for every case of latent yaws prevented among the children, 100 extra doses of azithromycin had to be administered.

"Despite this success, eradication per se was not achieved," said Dr. Mitja, an infectious diseases researcher at Hospital Germans Trias i Pujol in Barcelona. "Efforts need to be maintained until the target is achieved."

The disease was particularly effective at rebounding among children ages 6 to 10 years.

"The reason why the intervention did not get all the way to elimination is not clear, but it may be related to several factors like spillover of cases from the wards in the control group to the wards in the experimental group, or an insufficient number of latent cases treated, or active cases that were missed," Dr. Mitja said.

"It is extremely difficult to reach the whole population in an endemic area due to the lack of official censuses, which may cause some to be left behind unintentionally.," he added. "Also, most of these populations live off an informal economy which might involve frequent traveling (for selling products for day-to-day survival, for instance), which further hinders the capacity of reaching the whole of the population when deploying a mass drug administration."

The cost of the two interventions is similar, said Dr. Mitja.

There were only three cases of antibiotic resistance, and those patients were successfully treated with injectable penicillin.

"The appearance of azithromycin-resistant cases is a heads up on the need to perform continuous monitoring for antibiotic resistance for early identification and stopping the spread," Dr. Mitja said.

"We are a step closer to achieving the eradication of an infectious disease, the second in history, after smallpox," he said. "The development of eradication strategies is relevant to other infectious diseases which is a critical field for the well-being of humanity in the future. In the coming decades, it is expected that there will be new emerging infections, and some may be more dangerous than Covid-19; hence the need for research on disease control and eradication."

SOURCE: https://bit.ly/3eE1i0j The New England Journal of Medicine, online January 5, 2022.

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