New vaccine against Strep A could drastically cut antibiotic use for sore throats, study suggests

A new study published in the journal eBiomedicine Predicts whether widespread introduction of a vaccine against group A Streptococcus (Strep A) can reduce the use of antibiotics for sore throat.

Study: Antibiotic consumption for sore throat and the potential impact of a vaccine against group A streptococcus: a systematic review and modeling study. Image credit: goodluz/Shutterstock.com

Introduction

Most sore throats are caused by viral infections; However, strep is the main cause of acute bacterial pharyngitis or tonsillitis. Clinically, viral and bacterial sore throats are associated with similar symptoms. Distinguishing between viral and bacterial infections by diagnostic tests is both expensive and time-consuming, thus limiting their use in poor settings.

In some cases, these infections can cause serious complications, including streptococcal toxic shock syndrome (TSS), acute rheumatic fever progressing to rheumatic heart disease, and post-streptococcal glomerulonephritis. As a result, precautionary antibiotics are often prescribed against Strep A, the second and third leading cause of antibiotic prescribing in Europe and the US, respectively.

The development of a Strep A vaccine has been proposed as a global priority by the World Health Organization (WHO).“

What does the study show?

The current study estimates current antibiotic consumption rates for sore throats in absolute and relative terms, identifies antibiotics prescribed for this indication, and estimates reductions that could potentially follow the rollout of strep A vaccines.

Researchers analyzed nearly 100 studies of antibiotic use for sore throats from 38 countries. On average, five courses of antibiotics were prescribed for sore throats per 100 population annually.

Moreover, one in 20 antibiotic courses were used worldwide, with this use rate reaching one in seven in some countries. The average rate among young people was about 13, while for adults, it was six per 100 population per year.

Based on 2020 projections for empirical prescription rates, an estimated 37 million antibiotic courses were prescribed to treat sore throats annually. In 2020, nearly nine million children aged five to 14 took antibiotics for a sore throat. Of these, approximately 50% of diagnoses were in response to strep A infections, resulting in approximately 600 million sore throats annually.

Studies on prescription rates were primarily performed in high-income countries (HICs), which most commonly include the United States, the United Kingdom, and two Scandinavian countries. The countries of origin of this study comprise about one-tenth of the world’s population of all ages and half of the population of high-income countries.

These countries comprise about 5% of the world’s children and only 1% of middle-income countries, compared to more than half of children in HICs. Low Income Countries (LICs) were not represented.

While penicillins were commonly prescribed for sore throats, macrolides, lincosamides, and other beta-lactams were also commonly prescribed. Amoxicillin-clavulanate was the most frequently mentioned antibiotic not used according to current country-specific guidelines.

Antibiotics are often prescribed due to patient stress, expectations, or fear of losing or damaging a good patient-practitioner relationship. However, prescribing antibiotics for patients who are unlikely to benefit can have significant health implications.

Suppose an effective vaccine against Strep A was introduced with about 10 years of protection and achieved 80% coverage. In that case, it is estimated that this would prevent nearly 3 million courses of antibiotics prescribed for sore throats in children aged five to 14, the group with the highest rates of use. This assumes more than 30% of current prescriptions, assuming providers will still prescribe at current rates when presenting with a sore throat.

Vaccination can reduce antibiotic prescriptions for sore throat by preventing a significant proportion of strep A infections. This would reduce antibiotic prescriptions for at least 7.5 million sore throats annually.

Vaccines can reduce antibiotic prescriptions by more than 40% with increased coverage and efficacy. HICs will significantly reduce antibiotic prescribing for sore throats, especially in the Netherlands, where prescription rates are low.

What are the effects?

It is difficult to ascertain the global use of antibiotics for sore throats and how much of these antibiotics are used to treat strep A infections.

Notably, no studies have been conducted in low- to middle-income countries (LMICs), despite the relatively high rates of serious complications following Strep-A in these countries. Thus, it is crucial to explore antimicrobial use for sore throat in these countries, as this may be a potential cause of antimicrobial resistance.

The current study does not account for the possibility of reduced need for global antibiotic use for strep throat or herd immunity against Strep A. Declining vaccine effectiveness over time is also not modeled.

Nevertheless, research results indicate that introducing an effective vaccine against Strep A can reduce antibiotic prescriptions for sore throats by at least 33%. The magnitude of this reduction will vary with behavioral changes and changes in antibiotic use as determined by health care providers.

Thus, the effect of vaccination on antibiotic prescribing rates is as great or greater than the effect of advanced vaccine parameters, including vaccine coverage, efficacy, or duration of protection.