Immunity to Vaccine-preventable Viral Infections in Australians Being Evaluated for Liver Transplantation

Characteristics of Anti-Measles Immunity in Lung Transplant Candidates

Measles has not yet been eradicated; therefore, its outbreaks are still reported throughout the world. Like any infection, measles is dangerous for immunocompromised patients. Levels of anti-measles IgG antibodies were measured in 157 patients aged 17 to 72, who were placed on the lung transplant waiting list. Measurements were undertaken by enzyme-linked immunosorbent assay (ELISA) using the VectoMeasles-IgG kit (Russia). The proportion of patients seronegative for measles was 19% (30/157). Correlation was detected between patients' age and their levels of anti-measles antibodies, with higher proportions of patients having undetectable titers (25.5-28.9%) or low antibody levels (38.3-44.4%) in the young age groups (17-29 and 30-39 years old). There were no differences between male and female patients in levels of anti-measles antibodies or in the proportion of seronegative individuals. Analyses of antibody levels with regard to type of disease revealed the highest rate of seronegative results in cystic fibrosis patients (34.4%, 11/32). Overall, 19% of lung transplant candidates, mostly young people and cystic fibrosis patients, did not have protective immunity against measles.

Seroprevalence of Measles, Mumps, Rubella, and Varicella-Zoster Virus and Seroresponse to the Vaccinations in Adult Solid Organ Transplant Candidates

BACKGROUND

Updating live vaccines such as measles, mumps, rubella, and varicella (MMRV) is an important step in preparing patients for solid organ transplant (SOT) to prevent morbidity from these preventable diseases. However, data for this approach are scarce. Thus, we aimed to describe the seroprevalence of MMRV and the efficacy of the vaccines in our transplant center.

METHODS

Pre-SOT candidates >18 y of age were retrospectively retrieved from SOT database in Memorial Hermann Hospital Texas Medical Center. MMRV serologies are routinely screened at the time of pretransplant evaluation. We divided patients into 2 groups: MMRV-positive group versus MMRV-negative group, patients with positive all MMRV serologies and with negative immunity to at least 1 dose of MMRV, respectively.

RESULTS

A total of 1213 patients were identified. Three hundred ninety-four patients (32.4%) did not have immunity to at least 1 dose of MMRV. Multivariate analysis was conducted. Older age (odds ratio [OR]: 1.04) and liver transplant candidates (OR: 1.71) were associated with seropositivity. Previous history of SOT (OR: 0.54) and pancreas/kidney transplant candidates (OR: 0.24) were associated with seronegativity. Among 394 MMRV seronegative patients, 60 patients received 1 dose of MMR vaccine and 14 patients received 1 dose of varicella-zoster virus vaccine without severe adverse events. A total of 35% (13/37) of patients who had follow-up serologies did not have a serological response.

CONCLUSIONS

A significant number of pre-SOT candidates were not immune to at least 1 dose of MMRV. This highlights the importance of MMRV screening and vaccinations pre-SOT. Postvaccination serological confirmation should be performed to evaluate the necessity for a second dose.

Long-Term Varicella Zoster Virus Immunity in Paediatric Liver Transplant Patients Can Be Achieved by Booster Vaccinations—A Single-Centre, Retrospective, Observational Analysis

Varicella is one of the most common vaccine-preventable infections after paediatric solid organ transplantation; thus, vaccination offers simple and cheap protection. However, children with liver disease often progress to liver transplantation (LT) before they reach the recommended vaccination age. As a live vaccine, varicella zoster virus (VZV) vaccination after transplantation is controversial; however, many case series demonstrate that vaccination may be safe and effective in paediatric liver transplant recipients. Only limited data exists describing long-term vaccination response in such immunocompromised patients. We investigated retrospectively vaccination response in paediatric patients before and after transplantation and describe long-term immunity over ten years, including the influence of booster-vaccinations. In this retrospective, single-centre study, 458 LT recipients were analysed between September 2004 and June 2021. Of these, 53 were re-transplantations. Patients with no available vaccination records and with a history of post-transplant lymphoproliferative disease, after hematopoietic stem cell transplantation and clinical chickenpox were excluded from this analysis (n = 198). In total, data on 207 children with a median annual follow-up of 6.2 years was available: 95 patients (45.9%) were unvaccinated prior to LT. Compared to healthy children, the response to vaccination, measured by seroconversion, is weaker in children with liver disease: almost 70% after one vaccination and 93% after two vaccinations. One year after transplantation, the mean titres and the number of children with protective antibody levels (VZV IgG ≥ 50 IU/L) decreased from 77.5% to 41.3%. Neither diagnosis, gender, nor age were predictors of vaccination response. Booster-vaccination was recommended for children after seroreversion using annual titre measurements and led to a significant increase in mean titre and number of protected children. Response to vaccination shows no difference from monotherapy with a calcineurin inhibitor to intensified immunosuppression by adding prednisolone or mycophenolate mofetil. Children with liver disease show weaker seroconversion rates to VZV vaccination compared to healthy children. Therefore, VZV-naïve children should receive basic immunization with two vaccine doses as well as those vaccinated only once before transplantation. An average of 2–3 vaccine doses are required in order to achieve a long-term seroconversion and protective antibody levels in 95% of children.

Immunity to varicella, measles, and mumps in patients evaluated for lung transplantation

Vaccine-preventable viral infections are associated with increased risk of morbidity and mortality in post-transplant patients on immunosuppression regimens. Therefore, we studied rates of immunity against vaccine-preventable viruses in lung transplantation (LTx) candidates and their associations with underlying lung disease and clinical characteristics. We retrospectively studied 1025 consecutive adult patients who underwent first-time evaluation for LTx at a single center between January 2016 and October 2018. Viruses studied included varicella zoster (VZV), measles, and mumps. Young age (17-48 years old) was negatively associated with immunity for VZV (OR 4.54, p < .001), measles (OR 15.45, p < .001) and mumps (OR 3.1, p < .001), as compared to those 65+. Many LTx candidates with cystic fibrosis (CF) had undetectable virus-specific antibody titers including: 13.5% for VZV, 19.1% for measles, and 15.7% for mumps with significant odds of undetectable titers for VZV (OR 4.54, p < .001) and measles (OR 2.32, p = .010) as compared to those without CF. Therefore, a substantial number of patients undergoing LTx evaluation had undetectable virus-specific antibody titers. Our results emphasize the importance of screening for immunity to vaccine-preventable infections in this population and the need for revaccination in selected patients to boost their humoral immunity prior to transplantation.

Optimizing virus protection in lung transplant recipients: Don't drop the ball

Meyer and Avery comment on the implications of a study by Hostetler et al. (page 2864), in which screening of a large group of lung transplant candidates revealed that some lacked humoral immunity to measles, mumps, and varicella, especially younger patients and those with cystic fibrosis.

Italian association for the study of the liver position statement on SARS-CoV2 vaccination

The vaccination campaign against Sars-CoV-2 commenced in Italy at the end of December 2020. The first ones to receive the immunization against the virus were the health workers and the residents of nursing homes, following which the vaccine would be available for the entire population, beginning with the most vulnerable individuals. SARS-CoV2 vaccines have been demonstrated to be safe for the general population, although no data for patients with liver diseases or those having undergone liver transplantation are available so far. The present position statement AISF is an attempt to suggest, based on the published data on the impact of Sars-Cov-2 infection in patients with chronic liver disease, a possible priority for vaccination for this category of patients.

Measles outbreak risk assessment for transplant candidates and recipients

Solid organ transplant (SOT) candidates and recipients are at risk of significant morbidity and mortality from infection, including those circulating in the community from unexpected outbreaks. In late 2018-summer of 2019, a measles outbreak occurred in the New York City area, with a total of 649 cases reported. We developed a systematic 3-part approach to address measles risk in our adult SOT program through: (a) identification of nonimmune adults living in outbreak ZIP codes, (b) education focused on risk reduction for patients from outbreak ZIP codes, and (c) risk reduction for nonimmune patients. All waitlisted or previously transplanted patients residing in outbreak areas received a measles patient education handout. The electronic medical record of patients born in or after 1957 was reviewed for serologic evidence of measles immunity. Measles immunity testing was performed in patients without documentation of immunity. Patients who tested nonimmune were offered MMR vaccination or intravenous immunoglobulin depending on their transplant phase and risk profile. Thus, we demonstrate successful implementation of a systematic risk assessment during a large measles outbreak to identify and protect at-risk SOT patients. As vaccine hesitancy persists, our strategies may be increasingly relevant to transplant centers and those caring for immunocompromised patients.

New blood-borne virus infections among organ transplant recipients: An Australian data-linked cohort study examining donor transmissions and other HIV, hepatitis C and hepatitis B notifications, 2000-2015

BACKGROUND

Blood-borne viral infections can complicate organ transplantation. Systematic monitoring to distinguish donor-transmitted infections from other new infections post transplant is challenging. Administrative health data can be informative. We aimed to quantify post-transplant viral infections, specifically those transmitted by donors and those reactivating or arising new in recipients.

METHODS

We linked transplant registries with administrative health data for all solid organ donor-recipient pairs in New South Wales, Australia, 2000-2015. All new recipient notifications of hepatitis B (HBV), C (HCV), or human immunodeficiency virus (HIV) after transplant were identified. Proven/probable donor transmissions within 12 months of transplant were classified using an international algorithm.

RESULTS

Of 2120 organ donors, there were 72 with a viral infection (9/72 active, 63/72 past). These 72 donors donated to 173 recipients, of whom 24/173 already had the same infection as their donor, and 149/173 did not, so were at risk of donor transmission. Among those at risk, 3/149 recipients had proven/probable viral transmissions (1 HCV, 2 HBV); none were unrecognized by donation services. There were no deaths from transmissions. There were no donor transmissions from donors without known blood-borne viruses. An additional 68 recipients had new virus notifications, of whom 2/68 died, due to HBV infection.

CONCLUSION

This work confirms the safety of organ donation in an Australian cohort, with no unrecognized viral transmissions and most donors with viral infections not transmitting the virus. This may support targeted increases in donation from donors with viral infections. However, other new virus notifications post transplant were substantial and are preventable. Data linkage can enhance current biovigilance systems.

Measles, mumps, rubella, and varicella-zoster virus serology and infections in solid organ transplant recipients during the first year post-transplantation

BACKGROUND

Mumps, measles, rubella, and varicella-zoster viruses (MMRV) may cause severe infections in seronegative adult solid organ transplant (SOT) recipients but can be prevented by vaccination. We aimed to determine MMRV serostatus in adult SOT recipients before and one-year post-transplantation as well as evidence of MMRV infections in a large, prospective cohort of SOT recipients.

METHODS

A prospective study of 1182 adult SOT recipients included in the Management of Posttransplant Infections in Collaborating Hospitals (MATCH) cohort from 2011 to 2017 with a one-year follow-up. Systematic monitoring of MMRV serology was performed prior to transplantation and one-year post-transplantation. PCR was used to confirm viral replication in SOT-recipients presenting with clinical evidence of infection.

RESULTS

Among 1182 adult SOT recipients, 28 (2.4%), 77 (6.5%), 65 (5.5%), and 22 (1.9%) were seronegative for measles, mumps, rubella, and VZV, respectively, and 165 (14%) were seronegative for at least one of the MMRV viruses. One-year post-transplantation, 29/823 (3.5%) of seropositive SOT recipients had seroreverted, and 63/111 (57%) of seronegative SOT recipients seroconverted for at least one MMRV virus. No evidence of MMR infections was found, but 8 (0.7%) SOT recipients developed symptoms and had a positive VZV PCR.

CONCLUSIONS

A large proportion of SOT recipients were seronegative for at least one of the MMRV viruses. MMRV infections in SOT recipients may disseminate and become fatal, and although only few cases of VZV infection were detected, results from this study suggest increase attention towards vaccination of patients waiting for SOT.