Immunogenicity and reactogenicity of modified vaccinia Ankara pre-exposure vaccination against mpox according to previous smallpox vaccine exposure and HIV infection: prospective cohort study.

Background: Pre-exposure vaccination with MVA-BN has been widely used against mpox to contain the 2022 outbreak. Many countries have defined prioritized strategies, administering a single dose to those historically vaccinated for smallpox, to achieve quickly adequate coverage in front of low supplies. Using epidemiological models, real-life effectiveness was estimated at approximately 36%-86%, but no clinical trials were performed. Few data on MVA-BN immunogenicity are currently available, and there are no established correlates of protection. Immunological response in PLWH in the context of the 2022 outbreak was also poorly described. Methods: Blood samples were collected from participants eligible for pre-exposure MVA-BN vaccination before (T1) receiving a full course of vaccine (single-dose for vaccine-experienced or smallpox-primed and two-dose for smallpox vaccine-naïve or smallpox non-primed) and one month after the last dose (T2 and T3, respectively). MPXV-specific IgGs were measured by in-house immunofluorescence assay, using 1:20 as screening dilution, MPXV-specific nAbs by 50% plaque reduction neutralization test (PRNT50, starting dilution 1:10), and IFN-γ-producing specific T cells to MVA-BN vaccine, by ELISpot assay. Paired or unpaired t-test and Wilcoxon or Mann-Whitney test were used to analyse IgG and nAbs, and T-cell response, as appropriate. The probability of IgG and nAb response in vaccine-experienced vs. vaccine-naïve was estimated in participants not reactive at T1. The McNemar test was used to evaluate vaccination's effect on humoral response both overall and by smallpox vaccination history. In participants who were not reactive at T1, the proportion of becoming responders one month after full-cycle completion by exposure groups was compared by logistic regression and then analysed by HIV status strata (interaction test). The response was also examined in continuous, and the Average Treatment Effect (ATE) of the difference from baseline to schedule completion according to previous smallpox vaccination was estimated after weighting for HIV using a linear regression model. Self-reports of adverse effects following immunization (AEFIs) were prospectively collected after the first MVA-BN dose (T1). Systemic (S-AEFIs: fatigue, myalgia, headache, GI effects, chills) and local (L-AEFIs: redness, swelling, pain) AEFIs were graded as absent (grade 0), mild (1), moderate (2), or severe (3). The maximum level of severity for S-AEFIs and L-AEFIs ever experienced over the 30 days post-dose by vaccination exposure groups were analysed using a univariable multinomial logistic regression model and after adjusting for HIV status; for each of the symptoms, we also compared the mean duration by exposure group using an unpaired t-test. Findings: Among the 164 participants included, 90 (54.8%) were smallpox vaccine-experienced. Median age was 49 years (IQR 41-55). Among the 76 (46%) PLWH, 76% had a CD4 count >500 cells/µL. There was evidence that both the IgG and nAbs titers increased after administration of the MVA-BN vaccine. However, there was no evidence for a difference in the potential mean change in humoral response from baseline to the completion of a full cycle when comparing primed vs. non-primed participants. Similarly, there was no evidence for a difference in the seroconversion rate after full cycle vaccination in the subset of participants not reactive for nAbs at T1 (p = 1.00 by Fisher's exact test). In this same analysis and for the nAbs outcome, there was some evidence of negative effect modification by HIV (interaction p-value = 0.17) as primed people living with HIV (PLWH) showed a lower probability of seroconversion vs. non-primed, and the opposite was seen in PLWoH. When evaluating the response in continuous, we observed an increase in T-cell response after MVA-BN vaccination in both primed and non-primed. There was evidence for a larger increase when using the 2-dose vs. one-dose strategy with a mean difference of -2.01 log2 (p ≤ 0.0001), after controlling for HIV. No evidence for a difference in the risk of developing any AEFIs of any grade were observed by exposure group, except for the lower risk of grade 2 (moderate) fatigue, induration and local pain which was lower in primed vs. non-primed [OR 0.26 (0.08-0.92), p = 0.037; OR 0.30 (0.10-0.88), p = 0.029 and OR 0.19 (0.05-0.73), p = 0.015, respectively]. No evidence for a difference in symptom duration was also detected between the groups. Interpretation: The evaluation of the humoral and cellular response one month after the completion of the vaccination cycle suggested that MVA-BN is immunogenic and that the administration of a two-dose schedule is preferable regardless of the previous smallpox vaccination history, especially in PLWH, to maximize nAbs response. MVA-BN was safe as well tolerated, with grade 2 reactogenicity higher after the first administration in vaccine-naïve than in vaccine-experienced individuals, but with no evidence for a difference in the duration of these adverse effects. Further studies are needed to evaluate the long-term duration of immunity and to establish specific correlates of protection. Funding: The study was supported by the National Institute for Infectious Disease Lazzaro Spallanzani IRCCS "Advanced grant 5 × 1000, 2021" and by the Italian Ministry of Health "Ricerca Corrente Linea 2".

Pharyngo-tonsillar involvement of Mpox in a cohort of men who have sex with men (MSM): A serious risk of missing diagnosis.

During the 2022-outbreak, peculiar clinical presentations of Mpox have been described, some of which can make the diagnosis of the disease extremely challenging. Here we report a case series of fourteen patients with Mpox pharynogotonsillar involvement (PTI) seen at National Institute for Infectious Diseases, "Lazzaro Spallanzani", in Rome, Italy from May to September 2022. All included patients were men who have sex with men (median age 38 years) reporting unprotected sex within three weeks from symptoms onset. Seven out of fourteen patients needed hospitalization due to uncontrolled pain, reduced airspace and difficulty swallowing, of whom five were effectively treated with tecovirimat or cidofovir. The remaining two patients were treated with symptomatic drugs. The typical Mpox muco-cutaneous manifestations were not observed simultaneously with PTI in three patients, two of whom developed the lesions after several days, while one never manifested them. Polymerase Chain Reaction (PCR) for Mpox virus was positive in oropharyngeal swab, saliva and serum. Although PTI occurs in only a small percentage of Mpox cases, its diagnosis is of utmost importance. In fact, this localization, if not identified, could lead to serious complications in the absence of early antiviral treatment and to missed diagnosis with an increased risk of disease transmission.

Risk Awareness as a Key Determinant of Early Vaccine Uptake in the Mpox Vaccination Campaign in an Italian Region: A Cross-Sectional Analysis.

BACKGROUND: we aim to investigate attitudes toward vaccination by analyzing empirical factors associated with vaccine acceptance in the Lazio region mpox vaccination (MpoxVax) campaign in Italy. METHODS: all subjects who accessed MpoxVax and signed the informed consent were prospectively enrolled in the MPOX-VAC Study and were asked to fill out an anonymous survey. Two endpoints were selected: 'delayed acceptance' and 'early acceptance', defined as access for vaccination >60 and ≤30 days from the vaccination campaign starting (VCS), respectively. RESULTS: over the study period, 1717 individuals underwent vaccination: 129 (7%) > 60 [1588 (92.5%) ≤ 60] and 676 (60%) ≤ 30 days from VCS. A bisexual orientation, a lower education level and a worse perceived physical and mental health were associated with delayed access to vaccination. Being pre-exposure prophylaxis (PrEP) users and, marginally, HIV positive; having a high perceived risk for mpox infection; and reporting high-risk behaviors like the use of recreational drugs/chems, sex under the influence of drugs and/or alcohol and having a higher number of principal sexual partners, were associated with early access to vaccination. CONCLUSIONS: according to our data, risk awareness was a major determinant of early MpoxVax acceptance. Conversely, worse perceived health status and a low educational level were critical factors associated with delayed vaccination.

Effect of tecovirimat on healing time and viral clearance by emulation of a target trial in patients hospitalized for mpox.

Tecovirimat is a treatment option for severe mpox, although randomized clinical trials are ongoing. The aim of the study is to assess the effect of tecovirimat on healing time and the extent of viral clearance by target trial emulation using observational data. Clinical and virological data of patients hospitalized for mpox were collected. Samples from the upper respiratory tract (URT) were grouped in two time points: T1 (median 6 days from symptoms onset) and T2 (median 5 days from T1). Patients were followed-up until recovery. Average treatment effect (ATE) in patients untreated versus treated with tecovirimat was estimated on time to healing and variation in viral load in URT, using a weighted and cloning analysis. Among the 41 patients included, 19 completed a course of tecovirimat. The median time from symptoms onset to hospitalization and to drug-starting was 4 days and 10 days, respectively. No improvement in healing time in treated versus untreated was observed. No difference by treatment group in time to viral clearance was detected by ATE fitted in a subset of 13 patients after controlling for confounders. We found no evidence for a large effect of tecovirimat in shortening healing time and viral clearance. While awaiting the results of randomized studies, the use of tecovirimat should be restricted to the clinical trial setting.

Lymphofollicular lesions associated with monkeypox (Mpox) virus proctitis.

In the recent 2022 monkeypox (Mpox) global outbreak, cases have been mostly documented among men who have sex with men. Proctitis was reported in almost 14% of cases. In this study, four Mpox-confirmed cases requiring hospitalizations for severe proctitis were characterized by clinical, virological, microbiological, endoscopic, and histological aspects. The study showed the presence of lymphofollicular lesions associated with Mpox virus rectal infection for the first time.

Human Arboviral Infections in Italy: Past, Current, and Future Challenges.

Arboviruses represent a public health concern in many European countries, including Italy, mostly because they can infect humans, causing potentially severe emergent or re-emergent diseases, with epidemic outbreaks and the introduction of endemic circulation of new species previously confined to tropical and sub-tropical regions. In this review, we summarize the Italian epidemiology of arboviral infection over the past 10 years, describing both endemic and imported arboviral infections, vector distribution, and the influence of climate change on vector ecology. Strengthening surveillance systems at a national and international level is highly recommended to be prepared to face potential threats due to arbovirus diffusion.

Kinetics of viral DNA in body fluids and antibody response in patients with acute Monkeypox virus infection.

We report the follow-up laboratory investigation of three MPXV cases infected in May-June 2022 from diagnosis to disease resolution, monitoring viral shedding in different body fluids and antibody kinetics. Out of 138 non-lesion samples, viral DNA was found in 92.3% saliva, 85.7% semen, 86.2% oropharyngeal swabs, 51.7% plasma, 46.1% stool, and 9.5% urine samples. Viral load quantified by digital PCR widely varied, but tend to be higher in oropharyngeal swabs, saliva, and stool. Replication competent virus was recovered from four out of seventeen samples, including 1 saliva, 1 oropharyngeal swabs, 1 semen, and 1 stool. The analysis of the antibody kinetics revealed that IgM, IgA, and IgG antibodies were detected within two weeks post-symptoms onset for all three patients, with IgG detected early on at day 4-8 and IgM and IgA showing lower titers along the time frame of the study. Antibody levels increased during the second week of illness with IgG reaching high titers.

Immunological signature in human cases of monkeypox infection in 2022 outbreak: an observational study.

BACKGROUND: An unprecedented global monkeypox outbreak started in May, 2022. No data are yet available about the dynamics of the immune response against monkeypox virus. The aim of this study was to describe kinetics of T-cell response, inflammatory profile, and pox-specific T-cell induction in patients with laboratory-confirmed monkeypox. METHODS: 17 patients with laboratory-confirmed monkeypox admitted at the Lazzaro Spallanzani National Institute for Infectious Diseases (Rome, Italy), from May 19, to July 7, 2022, were tested for differentiation and activation profile of CD4 and CD8 T (expression of CD38, PD-1, and CD57 assessed by flow cytometry), frequency of pox-specific T cells (by standard interferon-γ ELISpot), and release of interleukin (IL)-1ß, IL-6, IL-8, and tumour necrosis factor (TNF) in plasma (by ELISA). All patients were tested 10-12 days after symptoms onset. In a subgroup of nine patients with a laboratory-confirmed monkeypox, the kinetics of the immune response were analysed longitudinally according to timing from symptoms onset and compared with ten healthy donors (ie, health-care workers recruited from the same institution). FINDINGS: Among the 17 patients, ten were HIV negative and seven HIV positive, all with good viro-immunological status. On days 0-3 from symptom onset, patients with laboratory-confirmed monkeypox were characterised by a statistically significant reduction in CD4+ T cells (p=0·0011) and a concurrent increase of CD8+ T cells (p=0·0057) compared with healthy donors. A lower proportion of naive (CD45RA+CD27+) CD4+ T cells was observed in six (67%) of nine patients and a concomitant higher proportion of effector memory (CD45RA-CD27-) CD4+ T cells in all patients; this skewed immune profile tended to normalise over time. A similar differentiated profile was also observed in CD8+ T cells with a consistent expansion of terminally differentiated CD8+ T cells. Patients with monkeypox had a higher proportion of CD4+CD38+ and CD38+CD8+ T-cells than healthy donors, which normalised after 12-20 days from symptom onset. The expression of PD-1 and CD57 on CD4+ and CD8+ T-cells showed kinetics similar to that observed for CD38. Furthermore, the inflammatory cytokines (IL-1ß, IL-6, IL-8, and TNF) were higher in patients with monkeypox than in healthy donors and, although they decreased over time, they remained elevated after recovery. Almost all patients (15 [94%] of 16) developed a pox-specific Th1 response. No differences in immune cells profile were observed between patients with and without HIV, whereas paucysimptomatic patients (without systemic symptoms, with less than five skin lesions, and no other mucosal localisation of monkeypox) showed a less perturbed immune profile early after symptom onset. INTERPRETATION: Our data showed the immunological signature of monkeypox virus infection, characterised by an early expansion of activated effector CD4+ and CD8+ T cells that persisted over time. Almost all patients, even regardless of HIV infection, developed a poxvirus-specific Th1 cell response. These results might have implications on the expected immunogenicity of monkeypox vaccination, suggesting that it might not be necessary to vaccinate people who have already been infected. FUNDING: Italian Ministry of Health. TRANSLATION: For the Italian translation of the abstract see Supplementary Materials section.