Strep A Vaccine: Reducing Antibiotic Use in Sore Throats

A recent study published in the journal eBioMedicine forecasts whether widespread use of a vaccination against group A Streptococcus (Strep A) could reduce antibiotic use for sore throat.

Introduction

The majority of sore throats are caused by viral infections; nevertheless, Strep A is the most common cause of acute bacterial pharyngitis or tonsillitis. Clinically, viral and bacterial sore throats have comparable symptoms. Diagnostic techniques to distinguish between viral and bacterial illnesses are both expensive and time-consuming, restricting their usage in low-income settings.

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

What did the study reveal?

The current study analyzes current antibiotic consumption rates for sore throat in absolute and relative terms, identifies medicines prescribed for this indication, and predicts the reduction that could potentially result from Strep A vaccination implementation.

The researchers examined over 100 studies on antibiotic use for sore throat from 38 different countries. Every year, five courses of antibiotics were recommended for sore throat in every 100 people.

Furthermore, one in every 20 antibiotic courses was utilized globally, with some countries using one in every seven antibiotic courses. The average rate among young people was around 13, whereas it was six for every 100 individuals in adults.

According to 2020 forecasts for empiric prescription rates, 37 million antibiotic courses were prescribed each year to treat sore throats. In 2020, almost nine million youngsters aged five to fourteen received antibiotics for a sore throat. About half of these were in response to Strep A infections, which produce 600 million instances of sore throat each year.

Prescription rate studies were mostly conducted in high-income countries (HIC), the most common of which were the United States, the United Kingdom, and two Scandinavian countries. These studies’ countries of origin represented roughly one-tenth of the world’s all-age population and half of the population of high-income countries.

These countries accounted for approximately 5% of the world’s children, compared to more than half of children in HICs and only 1% in middle-income countries. There was no representation from low-income countries (LIC).

Penicillins were the most usually recommended antibiotics for sore throat, followed by macrolides, lincosamides, and other beta-lactams. Among antibiotics not utilized in accordance with current country-specific guidelines, amoxicillin-clavulanate was the most commonly mentioned.

Antibiotics are frequently recommended as a result of patient pressure, expectations, or the fear of losing or destroying a strong patient-practitioner relationship. However, providing antibiotics to people who are unlikely to benefit might have serious health consequences.

Assume a successful vaccination against Strep A was introduced, providing approximately 10 years of protection and achieving 80% coverage. In that situation, it is anticipated that it would save about three million antibiotic courses administered for sore throats in children aged five to fourteen, the age group with the highest consumption rates. This estimate accounts for more than 30% of current prescriptions, assuming that clinicians continue to prescribe at the current rate when faced with sore throats.

By preventing a major proportion of Strep A infections, vaccination could help cut medication prescriptions for sore throat. This would save at least 7.5 million antibiotic prescriptions for sore throats each year.

With improved coverage and efficacy, vaccines could lower antibiotic prescriptions by more than 40%. Antibiotic prescribing for sore throats would be greatly reduced by HICs, particularly in the Netherlands, where prescribing rates are low.

What are the consequences?

It is still difficult to determine global antibiotic use for sore throats and how much of this antibiotic is used to treat Strep A infections.

Notably, no studies were conducted in low- to middle-income countries (LMIC), despite the fact that these countries have greater rates of severe post-Strep A sequelae. Thus, investigating antimicrobial use for sore throat in these nations is critical, as this could be a source of antimicrobial resistance.

The current study does not take into account herd immunity to Strep A or the prospect of reduced global antibiotic use for sore throats. Vaccine efficacy declining over time was also not modeled.

Nonetheless, the study findings suggest that developing an effective Strep A vaccination could cut antibiotic prescriptions for sore throat by at least 33%. The magnitude of this reduction would depend on changes in healthcare providers’ prescribing habits and antibiotic consumption.

As a result, the effect of vaccination on antibiotic prescribing rates is equal to or greater than the effect of better vaccine characteristics such as vaccine coverage, effectiveness, or duration of protection.

For more information: Antibiotic consumption for sore throat and the potential effect of a vaccine against group A Streptococcus: a systematic review and modelling study. eBioMedicine.

doi:10.1016/j.ebiom.2023.104864.