Comparison of the immunogenicity of Dukoral® oral cholera vaccine between renal transplant recipients on either a calcineurin inhibitor or mycophenolate - A controlled trial

Immunologic response to SARS-CoV-2 mRNA vaccination in pediatric kidney transplant recipients

BACKGROUND

COVID-19 disease in kidney transplant (KT) recipients is associated with increased morbidity, mortality, and hospitalization rates. Unfortunately, KT recipients also have a reduced response to SARS-CoV-2 immunization. The primary aim of this study was to assess immunologic response to SARS-CoV-2 mRNA vaccines in pediatric kidney transplant recipients 12-18 years of age. Secondary aims were to assess response rates following a third immunization and determine factors that influence immunization response.

METHODS

Pediatric KT recipients in a single tertiary center received SARS-CoV-2 mRNA vaccination as per local protocol. SARS-CoV-2 immunoglobulin (IgG) was measured following second and/or third vaccination. Demographics including patient factors (age, gender, and underlying disease), transplant factors (time and type of transplant), and immunosuppression (induction, maintenance, and immunomodulatory therapies such as IVIG) were collected from the medical records.

RESULTS

Of 20 participants, 10 (50%) responded following a two-dose vaccine schedule, which increased to 15 (75%) after three doses. Maintenance immunosuppression affected immunologic response, with azathioprine demonstrating a higher rate of response to vaccine compared to mycophenolate (100% vs. 38%, p = 0.04). Increasing prednisolone dose had a negative impact on immunologic response (0.01 mg/kg/day increase: OR 1.60 95% CI 1.01 to 2.57). Tacrolimus dose and trough levels, age, time post-transplant, underlying disease, and other immunosuppression did not impact immunologic response.

CONCLUSIONS

Pediatric KT recipients had similar response rates following SARS-CoV-2 immunization as adult KT recipients. Immunologic response improved following a third immunization. Choice of antimetabolite and prednisolone dosing influenced the rate of response. A higher resolution version of the Graphical abstract is available as Supplementary Information.

SARS-CoV-2 Vaccines: Safety and Immunogenicity in Solid Organ Transplant Recipients and Strategies for Improving Vaccine Responses

Purpose of Review

While solid organ transplant (SOT) recipients are at the highest risk for severe complications and increased mortality from COVID19 disease, their vaccination against SARS-CoV-2 remains challenging due to fear of immune-mediated adverse events and suboptimal immune response. Our current review is aimed to summarize current knowledge about the safety and efficacy of SARS-CoV-2 vaccines, describe factors that are correlated with immune response, and discuss strategies to improve vaccine immunogenicity in SOT recipients.

Recent Findings

SARS-CoV-2 vaccines are safe in SOT recipients and not related to rejection or other major adverse events. The immune response to two doses of vaccine is suboptimal and correlated to age and magnitude of immunosuppression. Administration of a third vaccine dose brings to significant amplification of immune response.

Summary

This review strengthens the existing recommendation of vaccination by three doses of vaccine in all SOT recipients and completion of vaccination before transplantation if possible.

Immunogenicity of cholera vaccination in children with inflammatory bowel disease

The cholera vaccine can protect patients with inflammatory bowel disease (IBD) against both cholera and travelers' diarrhea. However, both immunosuppressive treatment and IBD can affect its vaccine immunogenicity. The aim of this study was to assess the immunogenicity and safety of the cholera vaccine in children with IBD. Children older than 6 years with diagnosed IBD were enrolled in this multicenter study. All patients were administered two doses of the oral cholera vaccine (Dukoral®). Anti-cholera toxin B subunit IgA and IgG seroconversion rates were evaluated in a group with immunosuppressive (IS) treatment and a group without IS treatment (NIS). Immunogenicity was assessed in 70 children, 79% of whom received IS treatment. Post-vaccination seroconversion was displayed by 33% of children, for IgA, and 70% of children, for IgG. No statistically significant differences were found in the immune responses between the IS and NIS groups: 35% vs. 27% (p = .90), for IgA, and 68% vs. 80.0% (p = .16), for IgG, respectively. One case of IBD exacerbation after vaccination was reported. The oral cholera vaccine is safe. The immunogenicity of the oral cholera vaccine in children with IBD was lower than previously observed in healthy ones. The treatment type does not seem to affect the vaccine immunogenicity.

Reduced humoral response to mRNA SARS-CoV-2 BNT162b2 vaccine in kidney transplant recipients without prior exposure to the virus

COVID-19 is associated with increased morbidity and mortality in transplant recipients. There are no efficacy data available regarding these patients with any of the available SARS-CoV-2 vaccines. We analyzed the humoral response following full vaccination with the BNT162b2 (Pfizer-BioNTech) in 136 kidney transplant recipients, and compared it to 25 controls. In order to exclude prior exposure to the virus, only participants with negative serology to SARS-CoV-2 nucleocapsid protein were included. All controls developed a positive response to spike protein, while only 51 of 136 transplant recipients (37.5%) had positive serology (p < .001). Mean IgG anti-spike level was higher in the controls (31.05 [41.8] vs. 200.5 [65.1] AU/mL, study vs. control, respectively, p < .001). Variables associated with null humoral response were older age (odds ratio 1.66 [95% confidence interval 1.17-2.69]), high-dose corticosteroids in the last 12 months (1.3 [1.09-1.86]), maintenance with triple immunosuppression (1.43 [1.06-2.15]), and regimen that includes mycophenolate (1.47 [1.26-2.27]). There was a similar rate of side effects between controls and recipients, and no correlation was found between the presence of symptoms and seroconversion. Our findings suggest that most kidney transplant recipients remain at high risk for COVID-19 despite vaccination. Further studies regarding possible measures to increase recipient's response to vaccination are required.

Immunizations in Chronic Kidney Disease and Kidney Transplantation

PURPOSE OF REVIEW

Infection is a significant cause of morbidity and mortality in both patients with chronic kidney disease (CKD) and in recipients of a kidney transplant (KT). We review the current data in patients with CKD, on dialysis, and in KT recipients to provide further guidance for clinicians regarding vaccine optimization in this patient population.

RECENT FINDINGS

This patient population remains under-vaccinated and thus more vulnerable to vaccine-preventable illness. Despite diminished responses to immunization in this population, significant protection is generally achieved.

SUMMARY

Vaccines are an important preventative tool and offer protection against infection. In the setting of suboptimal and waning immunity in this patient population, future studies are indicated to determine optimal vaccination regimens.

Influence of immunosuppression on seroconversion against SARS-CoV-2 in two kidney transplant recipients

Solid organ transplant recipients are at risk for infectious complications due to chronic immunosuppression. The outbreak of coronavirus disease 2019 (COVID‐19) in the United States has raised growing concerns for the transplant patient population. We seek to add to the current limited literature on COVID‐19 in transplant recipients by describing the clinical course of two kidney transplant recipients with SARS‐CoV‐2 infection monitored by both RT‐PCR and serology. Through careful adjustment of their immunosuppression regimen, both patients had excellent recovery with intact graft function and development of anti‐SARS‐CoV‐2 antibodies.

Burden of typhoid fever and cholera: similarities and differences. Prevention strategies for European travelers to endemic/epidemic areas

The burden of diarrheal diseases is very high, accounting for 1.7 to 5 billion cases per year worldwide. Typhoid fever (TF) and cholera are potentially life-threatening infectious diseases, and are mainly transmitted through the consumption of food, drink or water that have been contaminated by the feces or urine of subjects excreting the pathogen. TF is mainly caused by Salmonella typhi, whereas cholera is caused by intestinal infection by the toxin-producing bacterium Vibrio cholerae. These diseases typically affect low- and middle-income countries where housing is overcrowded and water and sanitation are poor, or where conflicts or natural disasters have led to the collapse of the water, sanitation and healthcare systems. Mortality is higher in children under 5 years of age. Regarding their geographical distribution, TF has a high incidence in sub-Saharan Africa, India and south-east Asia, while cholera has a high incidence in a few African countries, particularly in the Horn of Africa and the Arabian Peninsula. In the fight against these diseases, preventive measures are fundamental. With modern air travel, transmissible diseases can spread across continents and oceans in a few days, constituting a threat to global public health. Nowadays, people travel for many reasons, such as tourism and business. Several surveys have shown that a high proportion of travelers lack adequate information on safety issues, such as timely vaccination and prophylactic medications. The main objective of this overview is to provide information to help European travelers to stay healthy while abroad, and thus also to reduce the potential importation of these diseases and their consequent implications for public health and society. The preventive measures to be implemented in the case of travel to countries where these diseases are still endemic are well known: the adoption of safe practices and vaccinations. It is important to stress that an effective preventive strategy should be based both on vaccinations and on hygiene travel guidelines. Furthermore, the emergence of multidrug-resistant strains is becoming a serious problem in the clinical treatment of these diseases. For this reason, vaccination is the main solution.