Background: Physical activity is an important part of healthy lifestyle and should be continued during low-risk pregnancy. Several studies have suggested that most pregnant women had no contraindications to perform exercises. The aim of the study was to assess the acute effect of an exercise test up to refusal and a chronic impact of an 8-week HIIT program on albuminuria and kidney function in the 2nd and 3rd trimester of pregnancy. Material and Methods: A group of 36 pregnant women was studied. At the beginning of the study, all participants had normal kidney function and albuminuria at rest. Nineteen women participated in an 8-week HIIT program (HIIT group), and seventeen in an educational program (EDU group). Before and after the training or education programs, a progressive exercise test up to volitional exhaustion on a cycloergometer was conducted. Several biochemical measurements were performed to assess changes in the kidney function. Results: After a short exercise test, some unexpected findings were observed: the fractional excretion of urea and uric acid increased (FeUrea from 41.25 to 50.05%; FeUA from 7.18 to 8.04%), and serum uric acid significantly decreased (sUA from 3.35 to 3.28mg/dL). Although the 8-week HIIT program had no impact on the kidney function at rest, the interesting finding was that albuminuria significantly increased only in the EDU group. Conclusion: Changes in the kidney function after a short very intense exercise in pregnancy were typical of healthy women, but there was no negative impact on markers of renal hypoperfusion. The supervised HIIT program during pregnancy had no negative impact on the kidney function.

Cardiovascular diseases are the leading cause of death globally. Studies indicate a higher prevalence of cardiovascular risk factors such as obesity, smoking, diabetes, hyperuricaemia, and lipid metabolism disorders among seafarers. The presented literature review highlights a significant gap in current data regarding the prevalence, clinical course, and prognosis of numerous cardiological conditions in this occupational group. The study focused primarily on coronary artery disease, heart failure, atrial fibrillation, and arterial hypertension among seafarers. Recently, there has been a growing emphasis on the intensification of preventive measures as well as early diagnosis of cardiovascular diseases. Seafarers represent an occupational group that may significantly benefit from individualized diagnostic and therapeutic strategies. The use of modern technologies - such as advanced echocardiographic techniques for risk stratification and mobile devices for arrhythmia detection - may significantly improve the effectiveness of identifying diseases before the onset of complications, particularly in situations where access to medical supervision is limited both during work and free time on the ship due to specific conditions at sea.

Malaria is a major international public health problem. The risk of acquiring malaria varies depending on the intensity of transmission and adherence to mosquito precautions and prophylaxis recommendations. Severe malaria can cause significant multiorgan dysfunction, including acute kidney injury (AKI). Intravenous artesunate is the treatment of choice for severe malaria in non-endemic areas. One of the possible events connected with the lifesaving effects of artemisins is post-artesunate haemolysis (PADH), which may be potentially dangerous and under-recognised. We present a case of a seafarer with severe Plasmodium falciparum malaria complicated with AKI and PADH, with a good response to steroid treatment. This case highlights the need for malaria prophylaxis in business travellers, e.g., seafarers to malara-endemic regions, and close supervision of patients with malaria even after the completion of antimalarial treatment due to the possibility of late complications.

The clinical context of drug interactions detected by automated analysis systems is particularly important in older patients with multimorbidities. We aimed to provide unique, up-to-date data on the prevalence of potentially inappropriate medications (PIMs) and drug–drug interactions (DDIs) in the Polish geriatric population over 80 years old and determine the frequency and the most common PIMs involved in DDIs. We analyzed all non-prescription and prescription drugs in a representative national group of 178 home-dwelling adults over 80 years old with excessive polypharmacy (≥10 drugs). The FORTA List was used to assess PIMs, and the Lexicomp® Drug Interactions database was used for DDIs. DDIs were detected in 66.9% of the study group, whereas PIMs were detected in 94.4%. Verification of clinical indications for the use of substances involved in DDIs resulted in a reduction in the total number of DDIs by more than 1.5 times, as well as in a nearly 3-fold decrease in the number of interactions requiring therapy modification and drug combinations that should be strictly avoided. The most common PIMs involved in DDIs were painkillers, and drugs used in psychiatry and neurology. Special attention should be paid to DDIs with PIMs since they could increase their inappropriate character. The use of automated interaction analysis systems, while maintaining appropriate clinical criticism, can increase both chances for a good therapeutic effect and the safety of the elderly during treatment processes.

BackgroundDepressive disorder is common among haemodialysis patients. The purpose of this study was to explore approaches to diagnosing depression in the context of a real-life setting, with the view of creating practical recommendations. It also aimed to evaluate the prevalence of depression and dementia.MethodsWe conducted a cross-sectional study in two Dialysis Centres in Poland. Cognitive functions were evaluated using Mini–Mental State Examination (MMSE). The screening for depressive symptoms was assessed using Beck Depression Inventory II (BDI-II). The diagnosis of major depressive disorder was confirmed by a psychiatrist using Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5). Sociodemographic and clinical data were also collected.ResultsInitially, 136 patients agreed to participate in the study. Dementia was found in 13% of the study group. Sixty-two patients did not agree to perform all the proposed tests and were not included in the analysis, which eventually consisted of 70 patients. According to BDI-II, depressive symptoms were present in 35.7% of patients, while the diagnosis of major depressive disorder (MDD) was confirmed by the psychiatrist in 25.7%. According to the ROC analysis the optimal cut-off score for diagnosing MDD using BDI-II was ≥13 points.ConclusionsThis study suggests that the regular screening for depressive symptoms, followed by a psychiatric consultation in selected patients, might improve diagnosing depression with the goal of achieving a higher quality of life and a lower mortality rate. It may also be a cost-effective model for the management of depression among the haemodialysis population.

Purpose Depressive disorder is common among hemodialysis (HD) patients and is associated with higher mortality rate. However, depression screening and treatment in dialysis population remains insufficient. The aim of the study was to show the prevalence of depression in patients on maintenance HD and to discuss the proper diagnostic approach, including dementia screening.Patients and methods We conducted a cross-sectional study that included 103 HD patients from one Dialysis Centre in Gdańsk (Poland). Cognitive functions were evaluated using Mini–Mental State Examination (MMSE). The screening for depression was assessed using Beck Depression Inventory (BDI-II). The diagnosis of depressive disorder was confirmed and its severity evaluated by psychiatrists based upon clinical assessment and scales. Sociodemographic, laboratory and dialysis data were also collected.Results According to BDI-II depressive symptoms were present in 43% of patients while the diagnosis of clinical Major Depressive Disorder (MDD) was confirmed by the psychiatrists in 13% of all subjects. In the depressive disorder group there was a prevalence of female and patients suffering from diabetes mellitus, levels of calcium phosphate index (CaxPi) were higher and Kt/V was lower. The optimal cut- off score for diagnosing major depressive disorder using BDI-II was ≥ 20 points. Cognitive impairment on the level of major neurocognitive disorder (dementia) was found in 18 % of the study group.Conclusions The prevalence of depression assessed using self- or clinician-administered questionnaires was higher than reported by clinical interview performed by the psychiatrist. Higher scores of CaxPi and lower Kt/V in depressive patients may suggest worse compliance in this group. The psychiatrist’s examination as a part of care at the Dialysis Centre could improve diagnosis of depression and its treatment with the goal to improve quality of life and lower the mortality rate in this population.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementThe authors received no specific funding for this work.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Independent Bioethics Committee for Scientific Research of Gdańsk Medical University, written consent (number NKBBN/194/2019)I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.Yes

Abstract Background and Aims Physical exercise is the best prophylaxis of many disorders and should be continued during uncomplicated pregnancy. Several studies suggested that most pregnant women had no contraindications to perform intensive exercises. In recently published studies the beneficial effect of high-intensity interval training (HIIT) on both mental health and reduction of excessive weight gain during pregnancy has been demonstrated. The knowledge regarding kidney function after exercise in pregnancy is very scarce and only few studies concerning this topic were published. The aim of this study was to estimate changes in markers of kidney function in healthy pregnant exercising women. Changes after single intensive exercise and after 8 week training program were analyzed. Method The group of 36 women in 2nd and 3rd trimester of pregnancy were recruited to the study. At the beginning of the study all participants had normal kidney function (serum creatinine level below 0.6 mg/dl) and albuminuria (uACR below 30 mg/g) in rest. 19 women participated in 8-week HIIT program and 17 women in 8-week educational program (EDU group). Before and after 8 week training and education programs a progressive maximal exercise test on cyclometer was performed. Several biochemical measurements were performed. Results Women from both groups revealed mild changes concerning kidney function in rest, typical for physiological pregnancy (e.g. low sodium, creatinine and uric acid levels). After progressive maximal exercise test some unexpected findings were found: the fractional excretion of urea and uric acid increased (FeUrea from 41.25 to 50.05%; FeUA from 7.18 to 8.04%) and serum uric acid decreased significantly (sUA from 3.35 to 3.28mg/dL). Other changes after short exercise were typical: significant increase of uACR (from 5.12 to 9.43mg/g), serum creatinine (from 0.52 to 0.56mg/dL) and urea (from 16.45 to 21.65 mg/dL), among others. The 8-week HIIT training program did not change kidney function in rest. In both groups a significant increase of eCrCl and sUA were observed. The interesting observation was that uACR increased significantly only in EDU group. Conclusion Changes in kidney function after short intensive exercise in pregnancy were typical for healthy subjects, but there was no negative impact on markers of renal hypoperfusion. It was probably related to increased renal blood flow occurring in healthy pregnancy. The supervised 8-week HIIT training program had no negative impact on kidney function. The possible positive impact of this training on albuminuria was suggested.

Abstract Objectives. Physical activity is an important part of healthy lifestyle and should be continued during uncomplicated pregnancy. Several studies have suggested that most of the pregnant women had no contraindications to perform exercises. The aim of the study was to assess the acute effect of maximal exercise test and chronic impact of an 8-week HIIT program on albuminuria and kidney function in the 2nd and 3rd trimester of pregnancy. Methods. A group of 36 pregnant women was studied. At the beginning of the study, all participants had normal kidney function and albuminuria at rest. Nineteen women participated in an 8-week HIIT program and seventeen in an educational program (EDU group). Before and after the training or education programs, a progressive maximal exercise test on cycloergometer was conducted. Several biochemical measurements were performed to assess changes in kidney function. Results. After short exercise test, some unexpected findings were observed: the fractional excretion of urea and uric acid increased (FeUrea from 41.25 to 50.05%; FeUA from 7.18 to 8.04%) and serum uric acid decreased significantly (sUA from 3.35 to 3.28mg/dL). The HIIT program had no impact on kidney function at rest. In both groups, significant increases in eGFR and sUA were observed. An interesting observation was that uACR increased significantly only in EDU group. Conclusion. Changes in kidney function after short intensive exercise in pregnancy were typical for healthy subjects, but there was no negative impact on markers of renal hypoperfusion. The supervised HIIT program had no negative impact on kidney function.

Mass casualty incident (MCI) is one of the most difficult situation in emergency medicine. Due to the specific conditions, MCIs occurring at sea are usually far more demanding than those happening on land. In this paper the authors would like to describe the MCIs, which have happened during almost 10 years of functioning of the Polish Telemedical Maritime Assistance Service (TMAS). First incident concerned a group of migrants floating on a raft on the Gulf of Mexico. The cause of the second incident was acute or-ganophosphate intoxication among the crew of the merchant ship. The third incident was triggered by the coronavirus disease 2019 (COVID-19). It is important to emphasize, that triage system may help in proper management of MCIs. Cooperation of the medical services, such as TMAS, local emergency medical staff, Search and Rescue (SAR) service and military force seems to be crucial in MCI managements occuring at sea. In case of any doubts, change of a course and heading to the nearest port or immediate evacuation should be taken into consideration. The authors believe that analysis of these incidents may help TMAS personnel all over the world to handle MCIs in the future. Med Pr. 2023;74(2)

BACKGROUND:The seafarers' professional group is one of the most numerous in the world. According to the statistics of the European Maritime Safety Agency (2020), there are approximately 280,000 people employed at sea in the European Union. The specific work environment on the ship (climatic, physical, chemical, psychological factors, etc.) is related to experiencing long-term stress. The World Health Organization considers work-related stressors to be very important determinants of health and disease. One of the basic psychological resources related to adaptation to demanding working conditions are strategies for coping with stress. The aim of the study is to assess the occurrence of harmful psychosocial factors in the work of seafarers and the stress coping strategies and their relationship with somatic diseases.MATERIALS AND METHODS:One hundred and fifteen seafarers who received a maritime health certificate participated in the study at the Occupational Medicine Clinic. The study was part of a larger project looking at the prevalence of cardiovascular risk factors among seafarers. The study used the Coping Questionnaire in Stressful Situations (CISS) (Endler and Parker) and a general questionnaire created for the purposes of the study.RESULTS:Thirty six per cent respondents were exposed to traumatic event and to having nightmares, 13% had been discriminated at least once in the workplace. A positive correlation was found between discrimination and depression, nightmares and trauma. In addition, people who admitted having experienced trauma slept shorter (also while at home) and experienced nightmares more often. The most common style of coping was task oriented (29; 28.5%), and avoidance oriented (15%). The study also found a positive correlation between depression and the style of emotion-oriented coping and avoidance-oriented coping.CONCLUSIONS:The specific working conditions and exposure to traumatic events have a negative impact on the health of seafarers by increasing the risk of depression and cardiovascular diseases. The coping styles with stress depend on the position in the ship hierarchy.

Objective: Major depressive disorder (MDD) is one of the most common psychiatric issues in hemodialysis population. However, the research on proper diagnostic tools and its treatment is still insufficient. The study was performed to investigate the safety and effectiveness of sertraline and agomelatine in a group of hemodialysis patients. Patients and Methods: 78 adult patients from one dialysis centre in Poland were included into the study. The Beck Depression Inventory II (BDI-II) was used to screen for depressive symptoms and was followed by the clinical interview with the psychiatrist. Nine patients diagnosed with major depressive disorder received antidepressant treatment with sertraline or agomelatine, according to the best clinical practice. The additional treatment with vortioxetine was used if the initial one was not effective. The time of observation was 24 weeks. The psychiatric follow up as well as the laboratory data were obtained during the course of observation. Results: All patients receiving sertraline achieved remission of depressive symptoms. In patients receiving agomelatine no remission was observed despite dose augmentation. The side effects of antidepressants were mild and did not result in treatment discontinuation. No abnormalities in liver enzymes levels were observed. In five cases the significant decrease of haemoglobin level was noticed, with no cases of bleeding reported. Conclusion: In patients receiving sertraline the antidepressant effect was satisfactory. No remission of depressive symptoms was observed in patients taking agomelatine. The side effects of antidepressants were mild and transient. Further research on depression treatment in hemodialysis patients is needed, including newer medications.

Department of Cardiology and Internal Diseases, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland Department of Cardiology, Medical University of Gdansk, Gdansk, Poland Department of Radiology, Medical University of Gdansk, Gdansk, Poland Department of Occupational, Metabolic and Internal Diseases, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland Department of Tropical and Parasitic Diseases, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland covid-19

INTRODUCTION The world's elderly population is growing dramatically. Pharmacotherapy in seniors is particularly challenging due to changes in metabolism, multimorbidity, and a great interest in nonpre-scription drugs.OBJECTIVES We aimed to provide up-to-date data on pharmacotherapy in the geriatric population of Poland, to determine factors predisposing to polypharmacy and excessive polypharmacy, and to identify seniors who are most likely to require multidisciplinary interventions in the field of pharmacotherapy.PATIENTS AND METHODS We analyzed the use of all prescription and nonprescription drugs taken within 2 weeks preceding the study in a representative national sample of 3014 home-dwelling seniors aged over 65 years. The variables of age, sex, place of residence, level of education, and multimorbidity were considered. Poststratification was used to balance the sample structure to match the Polish population of 2017.RESULTS Consumption of at least 1 drug was reported by 90.7% of the participants, and the mean number of drugs used was 5.01 (95% CI, 4.87-5.15). At least 1 nonprescription drug was used by 44.2% of the re-spondents, with a mean number of 0.52 (95% CI, 0.49-0.55). More than 5 drugs were taken by 53.5% of the entire population, while the use of more than 10 drugs was reported by 8.7% of the respondents, with multimorbidity as the most predisposing factor. Single-pill combinations accounted for 27.2% of medications.CONCLUSIONS The high prevalence of polypharmacy resulting from multimorbidity confirms the need for the implementation of combined medical and pharmaceutical care of the geriatric patients.

Chronically hemodialyzed (HD) patients are vulnerable population during a SARS-COV-2 pandemic. They are at high risk of developing very severe forms of COVID-19 disease. In this article we describe, for the first time to our knowledge, three HD patients (all males, aged 70, 70 and 74 years) vaccinated intramuscularly with two doses of the mRNA BNT162b2 vaccine (BionTech/Pfizer Comirnaty) in whom subsequent breakthrough SARS-CoV-2 infections developed. All patients achieved post-vaccine seroconversion for anti-spike antibodies with IgG titers of 227 AU/mL (cut-off, 13 UA/ml). SARS-CoV-2 infection was diagnosed 28, 44 and 48 days after the second dose of BNT162b2 and confirmed with the polymerase-chain-reaction (PCR) test. Two patients were asymptomatic of COVID-19 and didn't require hospitalization. The third patient reported only non-significant drop in oxygen saturation and was hospitalized. All patients were characterized by a moderate or even low post-vaccination neutralizing antibody titer but on the contrary a high production of these antibodies after infection. Perhaps this production of antibodies by memory B cells is responsible for the mild course of the disease and the likely reduction of mortality. These breakthrough cases in no way undermine the importance of the vaccinations and on the contrary, argue for their urgency.

Objectives: The aim of the presented study was to compare the health locus of control (HLC) between employed and unemployed patients after kidney transplantation (KT), and to investigate the relationship between HLC and the quality of life (QoL). Material and Methods: The study group consisted of 101 KT patients and the control group of 60 hemodialysis (HD) patients. The applied methods were: the Multidimensional Health Locus of Control Questionnaire (MHLC), the WHO Quality of Life Questionnaire (WHOQoL-BREF), and a survey collecting information on the socio-demographic status and work experience. Results: Overall, 57.5% of KT patients were employed and 42.5% were unemployed. In the HD group, 25% were employed and 71% were unemployed, while 4% did not disclose their employment status. The unemployed KT patients, in comparison with the employed ones, presented a higher feeling of the impact of chance on their health (unemployed M±SD 23.68±6.59; employed M±SD 21.02±4.57) and a lower level of QoL on the Somatic Scale (unemployed Me = 14.00, IQR = 3.00; employed Me = 1450, IQR = 3.00) and the Environmental Scale (unemployed M±SD 15.39±2.83; employed M±SD 16.85±3.24). In the employed KT group, the Internal Control Scale (MHLC) correlated with all QoL scales (the Somatic Scale: r = 0.292, p = 0.036; the Psychological Scale: r = 0.455, p = 0.001; the Social Scale: r = 0.304, p = 0.029; and the Environmental Scale: r = 0.307, p = 0.027). In the unemployed KT group, the Internal Control Scale (MHLC) correlated significantly with the Somatic Scale (r = 0.396, p = 0.013) and the Psychological Scale (r = 0.374, p = 0.019). Conclusions: The employed KT patients have a higher level of independence, with results indicating a strong internal type. Additionally, the working patients assess their QoL better, both in terms of their health condition and the organization of satisfying environment. The obtained knowledge about the psychological characteristics of KT patients may be useful for the occupational activation programs and psycho-education for those with weaker predispositions.

The emergence of a highly transmissible and a more pathogenic B.1.617.2 (delta) variant of SARS-CoV-2 has brought concern over COVID-19 vaccine efficacy and the increased risk of severe breakthrough infections. The objective of this study was to assess the frequency and the clinical characteristics of severe breakthrough COVID-19 cases recorded in 10 Polish healthcare units between 1 June and 31 December 2021, a period during which a rapid surge in the share of B.1.617.2 infections was seen, while a significant number of populations were already fully vaccinated. Overall, 723 individuals who completed the initial vaccination regime (fully vaccinated group) and an additional 18 who received a booster dose were identified—together, they represented 20.8% of all the COVID-19 patients hospitalized during the same period in the same healthcare institutions (0.5% in the case of a group that received a booster dose). Although laboratory and clinical parameters did not differ between both groups, patients who received a booster tended to have lower CRP, IL-6, PCT, and d-dimer levels and they required oxygen therapy less frequently. The most common early COVID-19 symptoms in the studied group were fatigue, cough, fever (>38 °C), and dyspnea. Individuals with no detectable anti-spike IgG antibodies constituted 13%; the odds of being a humoral non-responder to the vaccine were increased in patients aged >70 years. Fully vaccinated patients hospitalized after more than 180 days from the last vaccine dose were significantly older and they were predominantly represented by individuals over 70 years and with comorbidities, particularly cardiovascular disease. Contrary to mRNA vaccines, most patients vaccinated with adenoviral vector vaccines were infected within six months. A total of 102 fatal cases (14% of all deaths among vaccinated individuals; 0.7% in the case of a group that received a booster dose) were recorded, representing 17.6% of all the COVID-19 fatalities recorded in June–December 2021 in the considered healthcare units. The odds of death were significantly increased in men, individuals aged >70 years, patients with comorbidities, and those identified as humoral non-responders to vaccination; in fully vaccinated patients the odds were also increased when the second vaccine dose was given >180 days before the first COVID-19 symptoms. The mortality rate in immunocompromised subjects was 19%. The results indicate that compared to vaccinated individuals, severe COVID-19 and deaths in the unvaccinated group were significantly more prevalent during the B.1.617.2-dominated wave in Poland; and, it highlight the protective role of a booster dose, particularly for more vulnerable individuals.

The proper fluid and carbohydrates intake is essential before and during physical exercise, and for this reason most athletes drink beverages containing a high amount of free sugars. Sweetened soft drinks are also commonly consumed by those not doing any sport, and this habit seems to be both unhealthy and also the cause of metabolic problems. Recently, several sweeteners have been proposed to replace sugars in popular beverages. To examine the impact of free sugars and the popular sweetener xylitol on metabolic profile and the markers of kidney function and injury after exercise the present study was conducted with semi-professional football players. All participants were healthy, with a mean age of 21.91 years. Their sports skills were on the level of the 4th-5th division of the league. The subjects took part in four football training sessions. During each session they drank a 7% solution of sugar (sucrose, fructose, glucose) or xylitol. The tolerability of these beverages and well-being during exercise was monitored. Before and after each training session, blood and urine were collected. The markers of kidney function and injury, uric acid, electrolytes, complete blood count, CRP, serum albumin, serum glucose and the lipid profile were analyzed. The main finding of this study was that the xylitol beverage is the least tolerated during exercise and 38.89% of participants experienced diarrhea after training and xylitol intake. Xylitol also led to unfavorable metabolic changes and a large increase in uric acid and creatinine levels. A mean increase of 1.8 mg/dl in the uric acid level was observed after xylitol intake. Increases in acute kidney injury markers were observed after all experiments, but changes in urine albumin and cystatin C were highest after xylitol. The other three beverages (containing “free sugars” - glucose, fructose and sucrose) had a similar impact on the variables studied, although the glucose solution seems to have some advantages over other beverages. The conclusion is that sweeteners are not a good alternative to sugars, especially during exercise. Pure water without sweeteners should be drunk by those who need to limit their calorie consumption.Clinical Trial Registration:ClinicalTrials.gov, (NCT04310514)

The aim of this study was to analyze the waning of anti-spike (S) antibodies after mRNA vaccination against COVID-19 in maintenance dialysis patients, and to assess the safety and effectiveness of the complementary third dose. This was a prospective, longitudinal study in which we analyzed the kinetics of antibodies up to six months after a two-dose vaccination (first protocol) in infection-naïve dialysis patients (IN-Ds), previously infected dialysis patients (PI-Ds) and subjects without chronic kidney disease (the controls), as well as their humoral response to the third dose of the same mRNA vaccine (second protocol). The respective reduction in antibody titer after 3 and 6 months by 82.9% and 93.03% in IN-Ds (n = 109), 73.4% and 93.36% in PI-Ds (n = 32) and 75.5% and 88.8% in the controls (n = 20) was demonstrated. Consequently, a protective antibody titer above 141 BAU/mL was found in only 47.7% and 23.8% of IN-Ds after 3 and 6 months, respectively. After the third vaccine dose, a significant increase in antibody titer was observed in all groups, with increases by a factor of ×51.6 in IN-Ds, ×30.1 in the controls and ×8.4 in PI-Ds. The median antibody titer after the third dose differed significantly between groups, and was the highest in PI-Ds: PI-Ds, 9090 (3300–15,000) BAU/mL; the controls, 6945 (2130–11,800); IN-Ds, 3715 (1470–7325) (p < 0.001). In conclusion, we observed similar degrees of antibody waning in all patients. After 3 months, over half of the infection-naïve dialysis patients had a very low antibody titer, and almost twenty percent of them had no antibodies at all. The humoral response to the third dose was very good, raising their titer of antibodies to a higher level than those in the general population who have received the primary two-dose scheme. The results support the administration of a complementary third dose of the mRNA vaccine for dialysis patients as soon as possible.