How to Know If You Are at Risk for a Coinfection

Coinfection occurs when a host organism or cell is infected at the same time with more than one pathogen. While this can technically occur with many different combinations of infections, there are coinfections that commonly occur together related to various risk factors.

There are generally three clinical circumstances in which coinfections play a prominent role: Lyme disease, HIV, and hepatitis.

Lyme Disease

Lyme disease is considered a vector-borne disease (also referred to as VBD). Vectors are anything that acts as a carrier of the disease. In the case of Lyme disease, ticks are the sole vector.

Ixodes scapularis ticks, also known as hard-bodied ticks, are one of the biggest culprits of transmitting vector-borne diseases. The most common example of an Ixodes tick is the deer tick, found in the northeastern, mid-Atlantic, and north-central United States. The western black-legged tick (Ixodes pacificus) spreads the disease on the Pacific Coast.

If you have one or more coinfections with Lyme disease, you will likely exhibit more severe symptoms than someone who has only contracted Lyme disease.

While Bartonella is the most common coinfection that occurs along with Lyme disease, it's also important that your primary care provider looks for signs of Anaplasma coinfections when you exhibit more severe Lyme disease-associated symptoms.

Treating Lyme Disease Coinfections

Because it is often difficult to differentiate between Lyme disease and coinfections, your doctor may prescribe doxycycline, which treats Lyme disease and many other vector-borne diseases.

However, doxycycline may not be the best option for everyone, as it should be avoided in pregnant or nursing women as well as in children less than 8 years old. Other oral antibiotic options may include:

  • Amoxicillin
  • Cefuroxime axetil

For more severe cases that warrant IV antibiotic administration, you may see the following medications used:

  • Ceftriaxone
  • Cefotaxime
  • Penicillin G

HIV Coinfections

Due to the similar mode of transmission related to contracting human immunodeficiency virus (HIV), people infected with HIV are at risk of having a coinfection, most commonly with:

  • Tuberculosis
  • Hepatitis B
  • Hepatitis C

Risk Factors Related to HIV Coinfections

Hepatitis B (HBV) is a coinfection that is highly related to injection drug use and sexual contact. This may occur at the same time as HIV since the route of transmission is similar. Due to the similarity in infection, HBV testing is usually completed. If you are found to not have HBV and have a diagnosis of HIV, Hepatitis B vaccination is usually recommended.

Hepatitis C (HCV) coinfection can also be acquired via injection drug use and sexual contact. In 2009, approximately 20 out of 100 HIV-infected individuals also had HCV. However, it was identified that this risk was much higher in populations that engaged in injection drug use and men who have sex with men.

You should be tested for tuberculosis (TB) if you are diagnosed with HIV. TB that is latent may become active related to HIV infection.

Increased Risks Related to HIV Coinfections

Both HIV coinfections with HBV or HCV stand an increased risk of liver damage. Because of the increased risk to your liver, testing around the time of HIV confirmation is recommended. While HBV can be vaccinated against, HCV cannot.

Treating HIV Coinfections

Treatment of HIV and the coinfection is necessary. With a tuberculosis coinfection in a person with HIV, HIV therapy can cause immune reconstruction inflammatory syndrome (IRIS). To avoid an IRIS reaction, the treatment of tuberculosis should precede the treatment of HIV. In treating tuberculosis, HIV treatment is determined by your CD4 count, which coincides with your immune function.

The healthier your immune system when TB treatment is initiated, the longer you can delay HIV treatment. Depending on CD4 levels, you may start or continue HIV treatment anywhere from two to eight weeks after TB treatment is initiated.

While HIV can be treated at the same time as coinfections, and because management is more complex to reduce medication interactions and optimizing treatments, finding a doctor that has experience with treating HIV with coinfections is preferable.

Hepatitis Coinfections

Coinfection of Hepatitis B and Hepatitis C is common because both can be acquired by injection drug use, blood contact, and sexual contact. This coinfection combination is specifically at high risk of developing liver failure and progression to liver cancer. You can also have an increased risk of death due to liver failure if you do not treat the diseases. Current treatments related to Hepatitis C are very effective now, so do not delay getting treated.

Prevalence of HBV and HCV Coinfections

The prevalence of HBV and HCV coinfections is not well known, but is estimated to be anywhere from nine to 30 out of 100 people that have chronic hepatitis B will also have hepatitis C. It is believed that injection drug use, blood administration that is not properly screened, and unsterilized medical equipment represents the vast majority of coinfection cases of HBV and HCV.

Treating HBV and HCV Coinfections

Which disease is treated first will depend on the level of infection. If you have an active HBV infection, you will likely be started on HBV treatment either before or at the same time as HCV treatment. However, if you have low levels of HBV DNA, then you will likely have these levels checked periodically without HBV treatment while you have your HCV treatments.

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  1. Centers for Disease Control and Prevention. Lyme Disease: Transmission. Updated January 29. 2020.

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