Varicella Zoster Virus Linked to High Morbidity, Health Care Costs in Patients With HIV

Varicella zoster virus (VZV) infection causes significant morbidity and health care-associated costs among patients with HIV infection, According to results of a retrospective analysis published in Open Forum Infectious Diseases.

Researchers from the University of Calgary in Canada sourced data for this study from Southern Alberta Clinic. For this study, adult patients (N=3006) with HIV infection were evaluated for VZV serology, VZV-associated health care encounters, and VZV-associated health care costs between 2000 and 2020. The estimated odds of having positive vs negative VZV serology at baseline were adjusted via logistic regression.

Among 2628 patients with baseline serology results, baseline VZV-immunoglobulin (Ig)G-positivity was observed in  2503 (95.2%). Compared with baseline positivity, baseline negativity was associated with younger age (adjusted odds ratio [aOR], 0.79; 95% CI, 0.64-0.98; P =.02), being foreign-born (aOR, 2.64; 95% CI, 1.46-4.73; P <.01), non-White ethnicity (aOR, 0.94; 95% CI, 0.51-1.72; P <.01), a diagnosis of HIV infection later in life (P <.01), and completion of postsecondary education (P <.01).

Among 101 patients who were seronegative at baseline, 40 (39.2%) were subsequently vaccinated against VZV infection. Of these patients, 26 had no follow-up serology data, 9 did not seroconvert, and 5 achieved seroconversion.

There were 15 patients (0.6%) with documented receipt of VZV vaccination among those who were VZV-IgG-positive at baseline, of whom 80% received a subunit conjugate vaccine and 20% received a live attenuated vaccine.

During 29,768 total years of follow-up, 2883 patients had no VZV-related health care encounter, 104 visited an emergency department or urgent care center, and 29 were hospitalized. Patients who were admitted were less likely to be receiving antiretroviral therapy, to have detectable HIV viral loads, and to have lower CD4 cell counts (all P <.01) compared with those who had no documented VZV-associated health care encounter.

The median length of hospitalization for a VZV-related admission was 7.5 days. The total net cost for patients who were admitted was CAD$1,046,939, with a mean of CAD$27,551 per patient. After adjusting for inflation, the mean cost was CAD$31,292 per patient. Emergency department or urgent care center visits associated with an inflation-adjusted average of CAD$234 per patient-year.

This study may have limited generalizability as data were captured from patients residing in 1 geographical region.

According to the researchers, “further cost-effectiveness studies of shingles vaccination are warranted to address the continued burden of VZV and its complications in [patients with HIV infection].”

Disclosure: One author declared affiliations with industry. Please see the original reference for a full list of disclosures.

Reference

Zou J, Krentz HB, Lang R, Beckthold B, Fonseca K, Gill MJ. Seropositivity, risks, and morbidity from varicella-zoster virus infections in an adult PWH cohort from 2000–2020. Open Forum Infect Dis. 2022;9(8):ofac395. doi:10.1093/ofid/ofac395