Introduction
Viral blips (VB) are transient fluctuations of plasma HIV RNA values above the detection limit occurring in people with HIV (PWH) who are receiving effective antiretroviral therapy (ART). Not an infrequent event, occurring in at least one-quarter of patients on stable ART with undetectable viral loads (VL), their clinical significance is still a matter of debate, with some studies linking VB with viral failure. The pathophysiology of this phenomenon is complex and has not been clearly elucidated, but research has associated VB with vaccinations. Indeed, vaccines are immunostimulatory agents by definition and it has been postulated that they can induce a generalized inflammatory response with cytokine production, activating bystander cells harbouring latent HIV and thus leading to HIV reactivation and virion production.
We have recently described the case of a PWH who, having previously achieved stable viral suppression, experienced a VB after receiving a dose of COVID-19 vaccine, despite strict adherence to ART and plasma drug levels within the therapeutic range. Similar findings have been provided by Levy et al. and Milano et al., who reported 3/143 (2.1%) and 20/228 (8.9%) episodes after the second shot of COVID-19 vaccine in their cohort of PWH, respectively. To better understand the real incidence of VB among PWH vaccinated against COVID-19 and evaluate the variables associated with this phenomenon we designed this retrospective cohort study, in which we compared the occurrence of VB in the 12 months after the first vaccine shot with those recorded in the 12 months before.