Here we report a case of a woman (65 years of age) of European ancestry, diagnosed with HIV-1/HCV co-infection at the age of 37. Drug addiction from 1975 to 1990 and heterosexual intercourse were her main risk factors. Baseline immunological assessment CD4 + and CD8 + T-cell count were respectively 658 cells/µL and 679 cells/µL with a CD4+/CD8 + ratio of 1.0 and, according to the current international HIV guidelines at the time, antiretroviral therapy (ARV) was not carried out. No other co-infections or comorbidities were reported apart from anxiety and depressive disorders.
In March 1998 the first HIV-RNA Polymerase Chain Reaction (PCR) was performed, showing HIV-RNA < 200 copies/mL, genotype B, wild type. Since then, ARV therapy was not started due to the optimal CD4 + T-cell count and the concomitant viral suppression (< 20 cp/mL), spontaneously maintained during the following years.
In 2001 the patient was treated for HCV with interferon (IFN) plus ribavirin with a sustained virologic response.
In September 2017 she was vaccinated with pneumococcal and tetanus-diphtheria vaccine, and we observed a viral load increase at 93 cp/mL eight months after the infusion. In that occasion immunological status remained unaltered and viral load spontaneously resulted to be undetectable the following month.
Since then, she was regularly followed and refused to initiate any ARV therapy even though various reports in literature underlined the importance of beginning therapy in the elite controller population [13].
In 2021, due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, she was vaccinated with mRNA-BNT162b2 vaccine (Pfizer-BioNTech®) in the context of the Italian vaccination campaign. The first dose was administered on June 24th 2021 and the second on July 25th 2021. The last available VL was undetectable on March 24th 2021. During the regular semestral follow-up, in September 2021, we observed an increase of plasma HIV-RNA at 32 cp/mL, precisely two months after the second dose of vaccine.
Afterwards, a third dose of mRNA-BNT162b2 vaccine was scheduled on October 2nd. Due to detectable VL, it was decided to monthly control the immuno-virological status at the Outpatient Clinic. The highest HIV-RNA viremia was found to be 124 cp/mL on January 13th 2022, seven months after the first vaccine dose. On that occasion we measured total HIV-DNA by means of HIV-1 DNA Test PRO which allows the detection and quantification of total HIV-1 DNA, M group in whole blood samples and PBMC, resulting in 30 cp/10^6 PBMC. No data were available for reservoir measurement around the time of the first dose of vaccine. Total HIV-DNA was previously measured in 2017 with a home-made technique, and resulted to be undetectable.
During monthly follow-up controls, HIV-RNA gradually and spontaneously dropped, until it became undetectable on August 10th 2022. Concomitantly we observed a slight reduction of total HIV-DNA resulting in 13 cp/10^6 PBMC, below the limit of quantification of 20 cp/10^6 PBMC.
We performed COVID-19 serology, resulting in positive IgG 535 BAU/mL 10 months after the third dose of vaccine because the SARS-CoV-2 serology was not available immediately after the first/second dose. Throughout the follow-up, CD4 + and CD8 + T-cells and CD4+/CD8 + ratio, measured in September 2021, February 2022, March 2022 and November 2022, remained unaltered and the patient remained asymptomatic with a normal blood chemistry.