Group A Streptococcus (GAS) is a common bacterium that causes strep throat, an infection resulting in sudden, painful pharyngitis. Untreated strep throat can sometimes lead to complications like rheumatic fever. Taking proactive steps after contact with someone diagnosed with strep throat can significantly reduce the likelihood of infection and limit its spread. This guide explains how to minimize transmission and seek appropriate medical guidance following exposure.
Defining Close Contact and Incubation Period
Strep throat spreads through respiratory droplets released when an infected person coughs, sneezes, or talks. Close contact exposure typically involves living in the same household or having direct contact with oral secretions, such as sharing utensils, cups, or food. The bacteria can also be transferred by touching a contaminated object and then touching one’s own mouth or nose.
Understanding the timeframe for potential illness is helpful for monitoring. The incubation period, the time between exposure and the first appearance of symptoms, usually ranges from two to five days. During this window, the exposed person remains asymptomatic while the bacteria colonize the throat. Monitoring for symptoms like a sudden sore throat, fever, or difficulty swallowing should begin immediately after a known exposure.
Immediate Actions for Reducing Transmission Risk
While awaiting potential symptoms, behavioral and environmental controls are the first line of defense to prevent infection or limit household spread. Rigorous and frequent hand hygiene is the most effective method to disrupt the transmission cycle. Hands should be washed with soap and water for at least 20 seconds, especially after contact with the infected person, before eating, and after coughing or sneezing.
Since the bacteria can survive on surfaces, environmental disinfection is necessary to mitigate risk. High-touch surfaces, such as doorknobs, light switches, remote controls, and countertops, should be cleaned regularly with a household disinfectant. Items that contact the mouth, including dishes, cutlery, and drinking glasses, should be thoroughly washed in hot, soapy water or a dishwasher.
Any personal items belonging to the person with strep throat must be isolated and not shared. This includes towels, toothbrushes, and bedding, as these can harbor the bacteria. The infected person’s toothbrush should be replaced after they have been on antibiotics for a few days to prevent reinfection. The exposed person should monitor their health for the sudden onset of a sore throat, fever, or a sandpaper-like rash, which can indicate scarlet fever.
Medical Guidance on Testing and Preventative Treatment
Medical testing following exposure is typically based on the development of symptoms rather than the exposure itself. If characteristic symptoms appear, such as a sore throat, fever, painful swallowing, or white patches on the tonsils, consult a healthcare provider immediately. The provider will likely perform a rapid strep test (RST) using a throat swab, which yields results in minutes.
If the RST is negative but strep throat is still suspected, a throat culture may be sent to a laboratory, which takes 24 to 48 hours to provide a definitive result. Testing asymptomatic exposed persons is generally not standard practice, particularly for casual contact. However, a provider may recommend testing for asymptomatic close contacts in specific high-risk situations, such as during a community outbreak or if the contact is at increased risk for complications.
The use of prophylactic antibiotics for strep throat exposure is not routinely recommended for the general population. Administering antibiotics unnecessarily contributes to antibiotic resistance and carries the risk of side effects. Medical guidelines recommend monitoring the exposed person for symptoms and treating them with a full 10-day course of antibiotics only if the infection is confirmed by a positive test result.
There are rare exceptions where a healthcare provider may consider preventative antibiotics for a close contact. This includes individuals with a history of rheumatic fever, who are at risk for recurrence, or close contacts of a person with a serious invasive Group A Strep (iGAS) infection. Providers may also consider prophylaxis for close contacts over 65 years old or those with factors increasing their risk for severe infection. Any decision regarding preventative treatment must be made by a physician after evaluating the individual’s risk factors and the nature of the exposure.