A brand new study published within the journal eBioMedicine predicts whether the widespread introduction of a vaccine against group A Streptococcus (Strep A) could reduce using antibiotics for sore throat.

Study: Antibiotic consumption for sore throat and the potential effect of a vaccine against group A Streptococcus: a scientific review and modelling study. Image Credit: goodluz / Shutterstock.com

Introduction

Most sore throats result from viral infections; nevertheless, Strep A is the leading explanation for acute bacterial pharyngitis or tonsillitis. Clinically, viral and bacterial sore throats are related to similar symptoms. It’s each expensive and time-consuming to distinguish between viral and bacterial infections through diagnostic tests, thus limiting their use in poorer settings.

In some cases, these infections may result in severe complications, including streptococcal toxic shock syndrome (TSS), acute rheumatic fever culminating in rheumatic heart disease, and post-streptococcal glomerulonephritis. Because of this, precautionary antibiotics against Strep A are sometimes prescribed, with this being the second- and third-ranked cause for prescribing antibiotics in Europe and america, respectively.

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

What did the study show?

The present study estimates current antibiotic consumption rates for sore throat in absolute and relative terms, identifies the antibiotics prescribed for this indication, and estimates the reduction that would potentially follow the rollout of Strep A vaccines.

The researchers analyzed about 100 studies on antibiotic usage for sore throat from 38 countries. On average, five courses of antibiotics were prescribed for sore throat for each 100 populations annually.

Furthermore, one in 20 antibiotic courses was used worldwide, with this use rate reaching up to at least one in seven in some countries. The typical rate amongst young people was about 13, while for adults, it was six for each 100 populations yearly.

Based on 2020 estimates for empiric prescription rates, an estimated 37 million antibiotic courses were prescribed annually to treat sore throats. In 2020, about nine million children between the ages of 5 and 14 received antibiotics for sore throat. Of those, about 50% were in response to diagnosed Strep A infections, which cause roughly 600 million cases of sore throat yearly. 

The studies on prescription rates were primarily performed in high-income countries (HIC), probably the most common of which included the U.S., the UK, and two Scandinavian countries. The countries of origin of those studies comprised about one-tenth of the world’s all-ages population and half of the population of high-income countries.

These countries comprised about 5% of the world’s children in comparison with over half of kids in HIC and just one% of middle-income countries. Low-income countries (LIC) weren’t represented.

Penicillins were mostly prescribed for sore throat, with macrolides, lincosamides, and other beta-lactams also commonly prescribed. Amoxicillin-clavulanate was most steadily referenced amongst antibiotics not used in line with current country-specific guidelines.

Antibiotics are sometimes prescribed resulting from patient pressure, expectations, or the fear of losing or spoiling a superb patient-practitioner relationship. Nevertheless, antibiotic prescribing to patients who’re unlikely to profit can result in significant health effects.

Suppose an efficient vaccine was introduced against Strep A with roughly 10 years of protection and achieved 80% coverage. In that case, it’s estimated that it will prevent almost three million antibiotic courses prescribed for sore throats in children between five and 14 years of age, the group with maximum usage rates. This estimate accounts for over 30% of current prescriptions, assuming that providers will still prescribe at the present rate when presented with sore throats.

Vaccination could also reduce antibiotic prescriptions for sore throat by stopping a major proportion of Strep A infections. This might reduce antibiotic prescriptions for sore throat by a minimum of 7.5 million annually.

Vaccines could reduce antibiotic prescriptions by over 40% with increased coverage and efficacy. HICs would significantly reduce antibiotic prescribing for sore throats, especially within the Netherlands, where prescribing rates are low.

What are the implications?

It stays difficult to verify the worldwide use of antibiotics for sore throat and the way much of those antibiotics are used to treat Strep A infections.

Notably, no studies were performed in low- to middle-income countries (LMIC) despite the relatively higher rates of severe post-Strep A complications in these nations. Thus, exploring antimicrobial use for sore throat in these countries is crucial, as this may occasionally be a possible explanation for antimicrobial resistance.

The present study doesn’t account for herd immunity against Strep A or the potential of a lower need for global antibiotic use for sore throats. The waning of vaccine efficacy over time was also not modeled.

Nevertheless, the study findings indicate that introducing an efficient vaccine against Strep A could reduce antibiotic prescriptions for sore throat by a minimum of 33%. The extent of this reduction would vary with alterations in prescribing behaviors by healthcare providers and changes in antibiotic consumption.

Thus, the impact of vaccination on antibiotic prescribing rates is as high or higher than the effect of improved vaccine parameters, including vaccine coverage, efficacy, or duration of protection.