Secondary infection
A secondary infection occurs when a new infection arises simultaneously with, or follows, an initial (primary) infection. These infections can be caused by various pathogens, including bacteria and viruses, and are sometimes referred to as superinfections. Individuals with compromised immune systems, such as those living with HIV, are at a higher risk for secondary infections due to their reduced ability to fight off additional pathogens. Antibiotic use can also contribute, as these medications eliminate both harmful and beneficial bacteria, leaving the body vulnerable to new infections.
Secondary infections can occur through direct contact with pathogens or via nosocomial routes, which are infections acquired in medical settings. This risk is heightened in patients undergoing surgeries or those with existing health conditions. Pregnant women are particularly susceptible, as viral infections during this time can lead to adverse pregnancy outcomes. Preventive measures, including proper hygiene and vaccinations, are crucial in reducing the incidence of these infections. Treatment varies based on the type of secondary infection, and symptoms may be more severe than those of the primary infection. Understanding and mitigating the risk factors for secondary infections can significantly impact health outcomes and reduce associated healthcare costs.
Subject Terms
Secondary infection
- ALSO KNOWN AS: Superinfection
Definition
A secondary infection is a simultaneous infection or one that follows a treated initial (primary) infection. Also, a secondary infection can occur after reactivation of the initial infection. The secondary infection may be bacterial or viral, and it is often described as a superinfection.
Causes
Antibiotics taken to eliminate harmful bacteria from the body also eliminate necessary healthy (commensal) bacteria. Thus, a secondary infection can be caused by drug treatment of a primary infection that leaves the body immunocompromised and susceptible to more illnesses and infections; immunosuppression leads to secondary infection. A common example of secondary infection is superimposed bacterial pneumonia that is caused by a primary infection with influenza; the influenza damaged the lining of the lungs and nose, making the person more susceptible to bacterial infection of the respiratory tract.
Routes of Transmission
In addition to being transmitted by direct contact with a pathogen, secondary infections also can occur by nosocomial routes. A nosocomial infection is one that is acquired in a hospital or other medical setting during the course of a patient’s care. Infection can occur through contact with infected medical personnel and visitors or through surgery or other medical procedure. In this case, the specific organ focused on in surgery already may have abnormal tissue, leading to decreased immunity and a greater chance of secondary infection.
Pregnancy is a natural immunosuppressed state, and viral infections acquired by a woman during this time could cause birth defects, birth disorders, and other adverse pregnancy outcomes. Medical staff should distinguish between a secondary infection that occurred by reinfection with a different strain of a virus and reactivation of an initial infection, as the latter poses less risk for fetal transmission than does the former.
Prevention and Treatment
Preventive measures include proper hygiene techniques, such as handwashing, and avoiding contact with sick persons. Vaccinations, such as for influenza, are recommended to decrease the rate of primary infections that begin this pathway.
A secondary infection may present with symptoms more severe than those with a primary infection, mainly because of compromised immunity. The treatment of a secondary infection depends on the type of infection, and the need for antibiotics depends on the severity of symptoms.
Impact
Recognizing the risk factors for acquiring a secondary infection and implementing preventive measures reduce the morbidity and mortality associated with these infections. The economic implications of reducing these infections are significant too, especially in hospital settings.
Bibliography
Boskey, Elizabeth. "What Is a Secondary Infection?" VeryWellHealth, 24 Aug. 2023, www.verywellhealth.com/what-is-a-secondary-infection-3132823. Accessed 4 Feb. 2025.
Brachman, Philip S., and Elias Abrutyn, eds. Bacterial Infections of Humans: Epidemiology and Control. 4th ed. New York: Springer, 2009.
Downie, Fiona, et al. “Barrier Dressings in Surgical Site Infection Prevention Strategies.” British Journal of Nursing 19 (2010): S42-S46.
Ornoy, Asher, et al. “Effects of Primary and Secondary Cytomegalovirus Infection in Pregnancy.” Reproductive Toxicology 21 (2006): 399-409.
Stewart, Bruce, et al. “Imaging and Percutaneous Treatment of Secondarily Infected Hepatic Infarctions.” Interventional Radiology 190 (2008): 601-607.