After a rash of virus outbreaks — COVID-19, monkeypox, respiratory syncytial virus, and influenza — the latest outbreak is caused by a bacterium, strep A. Most parents know it as the cause of strep throat, a common cause of fever and sore throat in school-aged children, easily treated with penicillin. In yet another reminder that humans and the microbes that surround us are in constant tension, strep A has killed at least 94 children in Britain, 7 in Holland, 2 in the United States, and 2 in Canada this season. This penicillin-treatable bug kills 500,000 people globally every year.
More people die of strep A than measles, rotavirus, whooping cough, tetanus, and bacterial meningitis (all vaccine-preventable). Why? There is no vaccine.
There are reasons for this absence. First, deaths from strep A in high-income countries fell after antibiotics became widely available and access to health care improved. The vast majority of yearly deaths occur in low- and middle-income countries — nearly invisible to vaccine manufacturers in developed countries. Second, the US Food and Drug Administration imposed what was essentially a ban on further strep A vaccine testing in humans from 1970 to 2007 because testing of a poorly characterized vaccine in human subjects resulted in worse disease (despite safe testing in hundreds of thousands of people in the decades before). Third, no major vaccine company is working on a strep A vaccine. Finally, funding for strep A research increased from $1 million to $16 million as of last year, but remains chronically underfunded.
Strep A is a master of disguise. We are all familiar with strep throat. In North America and Europe, after a diagnostic test, penicillin is curative. Unfortunately, in under-resourced parts of the world, access to diagnosis and treatment is poor. Some children with untreated strep infections will develop inflammation of the heart and its valves, the joints, the skin, and the brain. Acute rheumatic fever may also develop. Unfortunately, future strep A infections may occur and each return further damages the heart valves. After a few decades, the heart begins to fail — like the heart failure that we see in older people but in 20- and 30-year-olds. Rheumatic heart disease caused by strep A is a major cause of death in pregnancy and poor pregnancy outcomes (still birth, low birth weight babies) in low- and middle-income countries.
Strep A is the main indication for treatment of sore throats, many of which are caused by viruses, which antibiotics don’t treat. Over 50 percent of prescribed antibiotics for sore throats are unnecessary; at least 30 percent of antibiotics prescribed in the United States are unnecessary. Sore throats account for a significant proportion of doctor visits, meaning that a lot of antibiotics are being wasted. In addition to hurting the “good bacteria” in us, the overuse of antibiotics has given rise to a host of bacteria that are now resistant to many antibiotics. A vaccine for strep A could stop a lot of unnecessary antibiotic use and the emergence of antibiotic resistance.
We have been working for the past three years at SAVAC, the Strep A Vaccine Global Consortium, to help the World Health Organization develop a road map for future strep A vaccines, create a business analysis to entice companies to get involved in vaccine development, and create a global health investment case to convince the funders of vaccine development, vaccine distribution, and countries affected by strep A that a vaccine, once developed, would be highly cost beneficial.
SAVAC has successfully advocated for more funding and raised awareness of strep A, but there is much more to be done. Hopefully, vaccines will enter clinical trials, new vaccines will be developed and tested, and companies that can manufacture vaccines in sufficient quantity and quality will join the fight. The world needs a safe and effective vaccine as soon as possible, a cost-effective and hugely beneficial intervention against this resurgent pathogen.
Jerome Kim is director general of the International Vaccine Institute. Andrew Steer is director of the Infection and Immunity Theme of the Murdoch Children’s Research Institute. They are codirectors of the Strep A Vaccine Global Consortium.