Patients infected with HIV have an increased risk of mortality and morbidity from diseases that are preventable with vaccines. Undervaccination of these patients poses a major concern, according to a literature review of the vaccine response in the adult patient with HIV published in The American Journal of Medicine.

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Despite the fact that data are limited, patients infected with HIV are advised to receive their age-specific and risk group−based vaccines, according to Firas El Chaer, MD, of the University of Maryland, Baltimore, and his colleague.

HIV patients are of particular concern regarding vaccination, because, despite the use of retroviral therapy, CD4+ T-lymphocytes in individuals infected with HIV remain lower than in those without HIV. In addition, HIV causes an inappropriate response to B-cell stimulation, which results in suboptimal primary and secondary response to vaccination, according to Dr. El Chaer and his colleague. Despite this and initial concerns about vaccine safety in this population, it is now recommended that adult patients infected with HIV receive their age-specific and risk group−based vaccines, they stated.

Inactivated or subunit vaccines

Haemophilus influenzae type b vaccine is not recommended under current guidelines for individuals older than age 18 with HIV infection, unless they have a clinical indication.

Vaccination against hepatitis A virus is recommended for HIV-infected patients who are hepatitis A virus seronegative and have chronic liver disease, men who have sex with men, intravenous drug users, and travelers to endemic regions. However, research has shown that the immunogenicity of the vaccine is lower in patients with HIV than in uninfected individuals. It was found that the CD4 count at the time of vaccination, not the CD4 low point, was the major predictor of the immune response.

Patients coinfected with HIV and hepatitis B virus have an 8-fold and 19-fold increase in mortality, respectively, compared with either virus monoinfection. Although vaccination is recommended, the optimal hepatitis B virus vaccination schedule in patients with HIV remains controversial, according to the authors. They indicated that new strategies to improve hepatitis B virus vaccine immunogenicity for those infected with HIV are needed.

Individuals infected with HIV have been found to have a higher risk of human papillomavirus (HPV) infection. The safety and immunogenicity results and prospect of benefits has led to a consensus on the benefit of vaccinating HIV-infected patients who meet the HPV vaccine age criteria, the authors indicated.

With regard to standard flu vaccinations: “An annual inactivated influenza vaccine is recommended during the influenza season for all adult individuals with HIV; however, a live attenuated influenza vaccine is contraindicated in this population,” according to the review.

Patients with HIV have a more than 10-fold increased risk of invasive meningococcal disease, compared with the general population, with the risk being particularly higher in those individuals with CD4 counts less than 200 cells/mm3 and in men who have sex with men in cities with meningococcal outbreaks. For these reasons, the “quadrivalent meningococcal vaccine is recommended for all patients with HIV regardless of their CD4 count, with 2-dose primary series at least 2 months apart and with a booster every 5 years.”

Pneumonia is known to be especially dangerous in the HIV-infected population. With regard to pneumonia vaccination, the 13-valent pneumococcal conjugate vaccine is recommended for all patients with HIV, regardless of their CD4 cell counts. According to Dr. El Chaer and his colleague, it should be followed by the 23-valent pneumococcal polysaccharide vaccine at least 8 weeks later as a prime-boost regimen, preferably when CD4 counts are greater than 200 cells/mm3 and in patients receiving ART.

“Tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccines are recommended once for all individuals infected with HIV, regardless of the CD4 count, with a tetanus toxoid and diphtheria toxoid booster every 10 years,” according to the review.

Live vaccines

Live vaccines are a concerning issue for HIV-infected adults and recommendations for use are generally tied to the CD4 T-cell count. The measles, mumps, and rubella vaccine seems to be safe in patients infected with HIV with a CD4 count greater than 200 cells/mm3, according to Dr. El Chaer and his colleague. Similarly, patients with HIV with CD4 counts greater than 200 cells/mm3 and no evidence of documented immunity to varicella should receive the varicella vaccine.

In contrast, the live, attenuated varicella zoster virus vaccine is not recommended for patients infected with HIV, and it is contraindicated if CD4 count is less than 200 cells/mm3. Recently, a herpes zoster subunit vaccine (HZ/su) was tested in a phase 1/2a randomized, placebo-controlled study and was found to be safe and immunogenic regardless of CD4 count, although it has not yet been given a specific recommendation for immunocompromised patients.

“With the widespread use of ART resulting in better HIV control, clinical vaccine development plans should include patients with HIV and other at-risk populations because they often carry much of the disease burden,” the authors concluded.

The study was not sponsored. Dr. El Chaer and his colleague reported that they had no conflicts.

SOURCE: El Chaer F et al. Am J Med. 2019. doi: 10.1016/j.amjmed.2018.12.011.