Double-dose Vaccine Research Articles

Numerical solution of fractional order model of measles disease with double dose vaccination

Numerical solution of fractional order model of measles disease with double dose vaccination

TRANSMISSION AND CONTROL DYNAMICS OF ROTAVIRUS DIARRHEA MODEL WITH DOUBLE DOSE VACCINATION

This study introduces a six-compartmental mathematical model (S, , , E, I, R) to examine the impact of administering a double dose vaccine on the dynamic spread of diarrhea within a community. The mathematical analysis shows the existence of equilibrium points for both disease-free and endemic states in the model. The basic reproduction number was determined using the Next Generation Matrix. Analysis has shown that the basic reproduction number which indicates the disease-free equilibrium point is locally asymptotically stable. Also, using a suitable Lyapunov functional for the model system expressed in state variables and parameters defining the dynamic characteristics of spread and control strategies of the rotavirus diarrhea to obtain the global stability of disease-free equilibrium point over time. A numerical simulation was carried out by Wolfram Mathematica to show the effect of a second-dose vaccine. The inclusion of a double-dose vaccine has been found to have a significant effect on completely eliminating the outbreak of diarrhea. This is evidenced by the local and global stability results, which indicate that effective measures have been taken to prevent the reintroduction or transmission of the disease, and if there may be a risk of outbreaks or reemergence of the disease, very little continuous monitoring and intervention strategies are required to maintain control as this should be taken seriously by medical practitioners or policy health makers.

Deterministic Double Dose Vaccination Model of COVID-19 Transmission Dynamics - Optimal Control Strategies with Cost-Effectiveness Analysis

In this study, we propose a deterministic double dose vaccination model of COVID-19 transmission dynamics optimal control with cost-effectiveness analysis. It is imperative for decision-makers and the government to prioritize the application of preventive and control measures for COVID-19 based on efficiency and costbenefit analysis. This is pivotal in resource-constrained regions where the disease is endemic. Thus, this work is mainly devoted with the development and analysis of an optimal control for COVID-19 dynamics with five timevarying functions; first dose vaccination, second dose vaccination, personal protection, testing or screening, and treatment. The model is qualitatively analysed with the overall goal to minimize the spread of COVID-19 and the costs related to control implementation with the aid of optimal control theory. The effect of adopting each control intervention in each of the three distinct groups which are created by classifying all conceivable combinations of at least three control interventions is demonstrated through the numerical simulations of the optimality system. Using the average cost-effectiveness ratio and incremental cost-effectiveness ratio techniques, the most economical control intervention is determined for each group. The study reveals that when the resources are readily available, application of the strategy that combines optimal first dose vaccination, personal protection, screening or testing and treatment is as efficient as implementing all the five optimal control interventions simultaneously as they both avert the same number of infections. However, in resource-limited communities when joint implementation of only three interventions is possible, the strategy combining personal protection, testing or screening and treatment is strongly recommended. Out of all the intervention options being considered, this strategy is also affirmed to be the most cost-effective overall. Economic evaluation of the control intervention strategies further suggests that combination of first dose vaccination, second dose vaccination, testing or screening and treatment is the most cost-effective strategy when implementation of only four interventions is strictly allowed.

Humoral immunity to SARS-CoV-2 in kidney transplant recipients and dialysis patients: IgA and IgG patterns unraveled after SARS-CoV-2 infection and vaccination

BackgroundInfection with SARS-CoV-2 in high-risk groups such as kidney transplant and dialysis patients is shown to be associated with a more serious course of the disease. Four years after the start of the COVID-19 pandemic, crucial knowledge on the immune responses in these patient groups is still lacking. Therefore, this study aimed at investigating the humoral immune response after a SARS-CoV-2 infection compared to vaccination as well as the evolution of immunoglobulins over time.MethodsKidney transplant recipients, patients on haemodialysis or on peritoneal dialysis and healthy controls were included in this longitudinal multicenter study. SARS-CoV-2 anti-RBD, anti-NP and anti-S1S2 immunoglobulin G (IgG) and A (IgA) as well as the neutralizing antibody capacity were measured.ResultsKidney transplant recipients had a significantly better humoral response to SARS-CoV-2 after infection (86.4%) than after a two-dose mRNA vaccination (55.8%) while seroconversion was comparable in patients on haemodialysis after infection (95.8%) versus vaccination (89.4%). In individuals without prior COVID-19, the IgG levels after vaccination were significantly lower in kidney transplant recipients when compared to all other groups. However, the IgA titres remained the highest in this patient group at each time point, both after infection and vaccination. A history COVID-19 was associated with higher antibody levels after double-dose vaccination in all patient categories and, while decreasing, titres remained high six months after double-dose vaccination.ConclusionKidney transplant recipients had a more robust humoral response to SARS-CoV-2 following infection compared to a two-dose mRNA vaccination, while patients on haemodialysis exhibited comparable seroconversion rates. Notably, individuals with prior COVID-19 exhibited higher IgG levels in response to vaccination. Hybrid immunity is thus the best possible defence against severe COVID-19 disease and seems also to hold up for these populations. Next, it is not clear whether the higher IgA levels in the kidney transplant recipients is beneficial for neutralizing SARS-CoV-2 or if it is a sign of disease severity.

Evaluating the impact of double dose vaccination on SARS-CoV-2 spread through optimal control analysis

This paper presents a new nonlinear epidemic model for the spread of SARS-CoV-2 that incorporates the effect of double dose vaccination. The model is analyzed using qualitative, stability, and sensitivity analysis techniques to investigate the impact of vaccination on the spread of the virus. We derive the basic reproduction number and perform stability analysis of the disease-free and endemic equilibrium points. The model is also subjected to sensitivity analysis to identify the most influential model parameters affecting the disease dynamics. The values of the parameters are estimated with the help of the least square curve fitting tools. Finally, the model is simulated numerically to assess the effectiveness of various control strategies, including vaccination and quarantine, in reducing the spread of the virus. Optimal control techniques are employed to determine the optimal allocation of resources for implementing control measures. Our results suggest that increasing the vaccination coverage, adherence to quarantine measures, and resource allocation are effective strategies for controlling the epidemic. The study provides valuable insights into the dynamics of the pandemic and offers guidance for policymakers in formulating effective control measures.

Beyond prevention: Unveiling the benefits of triple vaccination on COVID-19 severity and resource utilization in solid organ transplant recipients

ObjectiveDespite the widespread reduction in COVID-19-related morbidity and mortality attributed to vaccination in the general population, vaccine efficacy in solid organ transplant recipients (SOTR) remains under-characterized. This study aimed to investigate clinically relevant outcomes on double and triple-vaccinated versus unvaccinated SOTR with COVID-19. Study design and settingA retrospective propensity score-matched cohort study was performed utilizing data from the US Collaborative Network Database within TriNetX (n = 117,905,631). We recruited vaccinated and unvaccinated (matched controls) SOTR with COVID-19 over two time periods to control for vaccine availability: December 2020 to October 2022 (bi-dose, double-dose vaccine effectiveness) and December 2020 to April 2023 (tri-dose, triple-dose vaccine effectiveness). A total of 42 factors associated with COVID-19 disease severity were controlled for including age, obesity, diabetes, and hypertension. We monitored 30-day outcomes including acute respiratory failure, intubation, and death following a diagnosis of COVID-19. ResultsSubjects were categorized into two cohorts based on the two time periods: bi-dose cohort (vaccinated, n = 462; unvaccinated, n = 20,998); tri-dose cohort (vaccinated, n = 517; unvaccinated, n = 23,061).Compared to unvaccinated SOTR, 30-day mortality was significantly lower for vaccinated subjects in both cohorts: tri-dose (2.0% vs 7.5%, HR = 0.22 [95% CI: 0.11, 0.46]); bi-dose (3.7% vs 8.2%, HR = 0.43 [95% CI: 0.24, 0.76]). Hospital admission rates were similar between bi-dose vaccinated and unvaccinated subjects (33.1% vs 28.6%, HR = 1.2 [95% CI: 0.95, 1.52]). In contrast, tri-dose vaccinated subjects had a significantly lower likelihood of hospital admission (29.4% vs 36.6%, HR = 0.74 [95% CI: 0.6, 0.91]). Intubation rates were significantly lower for triple-vaccinated- (2.3% vs 5.2%, p < 0.05), but not double-vaccinated subjects (3.0% vs 5.2%, p > 0.05). ConclusionIn solid organ transplant recipients with COVID-19, triple vaccination, but not double vaccination, against SARS-CoV-2 was associated with significantly less hospital resource utilization, decreased disease severity, and fewer short-term complications. These real-world data from extensively matched controls support the protective effects of COVID-19 vaccination with boosters in this vulnerable population.

Side Effects of COVID-19 Vaccination among the Pregnant Women: A Cross-Sectional Study in a Tertiary Hospital of Bangladesh

Introduction: Pregnancy is a very special time for a woman and her family, although being pregnant is a stressful condition for every woman. The COVID-19 pandemic has made that condition more stressful. Clinical trials prove that COVID-19 vaccines are safe for pregnant women and also for lactating mothers. So WHO has approved vaccines for both above-mentioned groups. Hence, Bangladesh Government has taken the decision to vaccinate every pregnant woman against COVID-19 infection. Objectives: To assess the side effects of COVID-19 vaccination on pregnant women in a tertiary care hospital in Bangladesh Army. Methods: This cross sectional single-centered observational study was conducted in Combined Military Hospital (CMH) Dhaka from August 2021 to November 2021. Total 50 pregnant nullipara and multipara women with double dose vaccination were included. Relevant data were recorded in a preformed data collection sheet and analyzed by SPSS version 20. Results: Mean age of the participants was 19.2±10.8 years. The most commonly observed symptoms were pain in injection site, fatigue, swelling in injection site and myalgia. The most prevalent affected age group were 25-35 years. Among 48 participants, 20(41.6%) had co-morbidites. Two participants were found to have COVID-19 infection (4%) after vaccination. Conclusion: Side effects profile obtained from pregnant women in this study were non-life threatening. A recognized vaccine programme can be a relieving factor for pregnant women from increased stress and anxiety caused by COVID-19. JAFMC Bangladesh. Vol 19, No 1 (June) 2023: 34-37

Safety and Immunogenicity of the Convacell® Recombinant N Protein COVID-19 Vaccine.

We have developed Convacell®-a COVID-19 vaccine based on the recombinant nucleocapsid (N) protein of SARS-CoV-2. This paper details Convacell's® combined phase I/II and IIb randomized, double-blind, interventional clinical trials. The primary endpoints were the frequency of adverse effects (AEs) and the titers of specific anti-N IgGs induced by the vaccination; secondary endpoints included the nature of the immune response. Convacell® demonstrated high safety in phase I with no severe AEs detected, 100% seroconversion by day 42 and high and sustained for 350 days anti-N IgG levels in phase II. Convacell® also demonstrated a fused cellular and humoral immune response. Phase IIb results showed significant post-vaccination increases in circulating anti-N IgG and N protein-specific IFNγ+-producing PBMC quantities among 438 volunteers. Convacell® showed same level of immunological efficacy for single and double dose vaccination regimens, including for elderly patients. The clinical studies indicate that Convacell® is safe and highly immunogenic.

In-Hospital influenza vaccination to prevent cardiorespiratory events in the first 45 days after acute coronary syndrome: A prespecified analysis of the VIP-ACS trial

BackgroundInfluenza vaccination prevents major cardiovascular events in individuals presenting a recent acute coronary syndrome (ACS), however the early effect of an in-hospital double-dose vaccination strategy remains uncertain. MethodsThe VIP-ACS was a randomized, pragmatic, multicenter, open-label trial with a blinded-adjudication endpoint. Patients with ACS ≤ 7 days of hospitalization were randomized to an in-hospital double-dose quadrivalent inactivated influenza vaccine (double-dose) or a standard-dose influenza vaccine at 30 days post-randomization. The primary endpoint was a hierarchical composite of death, myocardial infarction, stroke, hospitalization for unstable angina, hospitalization for heart failure, urgent coronary revascularization, and hospitalization for respiratory infections, analyzed with the win ratio (WR) method in short-term follow-up (45-days after randomization). ResultsThe trial enrolled 1,801 patients (≥18 years old). Median participant age was 57 years, 70 % were male. There were no significant differences between groups on the primary hierarchical endpoint: there were 5.7 % wins in the double-dose in-hospital group and 5.5 % wins in the standard-dose delayed vaccination group (WR: 1.03; 95 % CI: 0.70–––1.53; P = 0.85). In a sensitivity analysis including COVID-19 infection in the hospitalizations for respiratory infections endpoint, overall results were maintained (WR: 1.03; 95 % CI 0.71–––1.51; P = 0.87). Results were consistent for major cardiovascular events only (WR: 0.82; 95 % CI: 0.48–––1.39; P = 0.46). No serious adverse events were observed. ConclusionIn patients with recent ACS, in-hospital double-dose influenza vaccination did not significantly reduce cardiorespiratory events at 45 days compared with standard-dose vaccination at 30 days post-randomization.

Mathematical Analysis of Covid-19 with Double Dose Vaccination and Treatment

A compartmental model of covid-19 with double dose vaccine based on a system of non-linear ordinary differential equations is formulated and theoretically analyzed. The model is divided into eight compartmental classes, namely, susceptible (S), first dose vaccinated ( second dose vaccinated exposed (E), asymptomatic (A), symptomatic (I), hospitalized (H), and recovery (R). There are several kinds of approval vaccines, and each has a different efficacy and mechanism of action for reducing the outbreak of epidemic. Fortunately, there is a mathematical precise scale can be used as an indicator to determine whether the disease will be eradicated or persisted in the population, that is a basic reproduction number The next generation method (NGM) is used to compute , before vaccination, and after two doses were taken. Comparison the results shows -clearly- the positive effect of the intrinsic efficacy of vaccine on reducing , and hence on eradication the epidemic.

A fractional modeling approach for the transmission dynamics of measles with double-dose vaccination

Measles, a member of the Paramyxoviridae family and the Morbillivirus genus, is an infectious disease caused by the measles virus that is extremely contagious and can be prevented through vaccination. When a person with the measles coughs or sneezes, the virus is disseminated by respiratory droplets. Normally, the appearance of measles symptoms takes 10–14 d following viral exposure. Conjunctivitis, a high temperature, a cough, a runny nose, and a distinctive rash are some of the symptoms. Despite the measles vaccination being available, it is still widespread worldwide. To eradicate measles, the Reproduction Number (i.e. R 0 < 1 ) must remain less than unity. This study examines a SEIVR compartmental model in the caputo sense using a double dose of vaccine to simulate the measles outbreak. The reproduction number R 0 and model properties are both thoroughly examined. Both the local and global stabilities of the proposed model are determined for R 0 less and greater than 1. To achieve the model’s global stability, the Lyapunov function is used while the existence and uniqueness of the proposed model are demonstrated In addition to the calculated and fitted biological parameters, the forward sensitivity indices for R 0 are also obtained. Simulations of the proposed fractional order (FO) caputo model are performed in order to analyse their graphical representations and the significance of FO derivatives to illustrate how our theoretical findings have an impact. The graphical results show that the measles outbreak is reduced by increasing vaccine dosage rates.

Transmission of COVID-19 in the presence of single-dose and double-dose vaccines with hesitancy: mathematical modeling and optimal control analysis

IntroductionThe unexpected emergence of novel coronavirus identified as SAR-CoV-2 virus (severe acute respiratory syndrome corona virus 2) disrupted the world order to an extent that the human activities that are core to survival came almost to a halt. The COVID-19 pandemic created an insurmountable global health crisis that led to a united front among all nations to research on effective pharmaceutical measures that could stop COVID-19 proliferation. Consequently, different types of vaccines were discovered (single-dose and double-dose vaccines). However, the speed at which these vaccines were developed and approved to be administered created other challenges (vaccine skepticism and hesitancy).MethodThis paper therefore tracks the transmission dynamics of COVID-19 using a non-linear deterministic system that accounts for the unwillingness of both susceptible and partially vaccinated individuals to receive either single-dose or double-dose vaccines (vaccine hesitancy). Further the model is extended to incorporate three time-dependent non-pharmaceutical and pharmaceutical intervention controls, namely preventive control, control associated with screening-management of both truly asymptomatic and symptomatic infectious individuals and control associated with vaccination of susceptible individuals with a single dose vaccine. The Pontryagin's Maximum Principle is applied to establish the optimality conditions associated with the optimal controls.ResultsIf COVID-19 vaccines administered are imperfect and transient then there exist a parameter space where backward bifurcation occurs. Time profile projections depict that in a setting where vaccine hesitancy is present, administering single dose vaccines leads to a significant reduction of COVID-19 prevalence than when double dose vaccines are administered. Comparison of the impact of vaccine hesitancy against either single dose or double dose on COVID-19 prevalence reveals that vaccine hesitancy against single dose is more detrimental than vaccine hesitancy against a double dose vaccine. Optimal analysis results reveal that non-pharmaceutical time-dependent control significantly flattens the COVID-19 epidemic curve when compared with pharmaceutical controls. Cost-effectiveness assessment suggest that non-pharmaceutical control is the most cost-effective COVID-19 mitigation strategy that should be implemented in a setting where resources are limited.DiscussionPolicy makers and medical practitioners should assess the level of COVID-19 vaccine hesitancy inorder to decide on the type of vaccine (single-dose or double-dose) to administer to the population.

A mathematical analysis of the impact of maternally derived immunity and double-dose vaccination on the spread and control of measles

Abstract Measles is a highly communicable viral infection that mostly affects children aged 5 years and below. Maternal antibodies in neonates help protect them from infectious diseases, including measles. However, maternal antibodies disappear a few months after birth, necessitating vaccination against measles. A mathematical model of measles, incorporating maternal antibodies and a double-dose vaccination, was proposed. Whenever ℛ 0 &lt; 1 {{\mathcal{ {\mathcal R} }}}_{0}\lt 1 , the model is shown to be locally asymptotically stable. This means that the measles disease can be eliminated under such conditions in a finite time. It was established that ℛ 0 {{\mathcal{ {\mathcal R} }}}_{0} is highly sensitive to β \beta (the transmission rate). A numerical simulation of the model using the Runge-Kutta fourth-order scheme was carried out, showing that varying the parameters to reduce ℛ 0 {{\mathcal{ {\mathcal R} }}}_{0} will help control the measles disease and ultimately lead to eradication. The measles-mumps-rubella (MMR) vaccine dosage should be adjusted for babies from recovered mothers, as maternal antibodies are usually high in such babies and can interfere with the effectiveness of the MMR vaccine.

Mathematical investigation of a two-strain disease model with double dose vaccination control policies

Antimicrobial resistance (AMR) is the microorganism's resistance to an antimicrobial drug developed and designed to handle an infection. A recent study showed that there were 1.27 million global deaths in 2019 attributable to AMR. In current decades, vaccination is the most effective treatment that can reduce the growing AMR by preventing the incidence of infectious diseases (directly or indirectly). Vaccination has become a popular treatment as this can reduce the number of circulating AMR strains and reduce the need for antimicrobial use. With a double-dose vaccination campaign, we analyzed drug-susceptible and drug-resistant pathogens for this survey. We considered the circumstances of positive invariances and boundedness with appropriate primary conditions. We have determined two basic reproduction numbers: one associated with drug-susceptible strain (R01) and the other with drug-resistant strain (R02). We also revealed that at any stage, one of the strain could spread in a population if max[R01, R02] > 1 and the disease fade-out if both are <1 (i.e., max[R01, R02] < 1). In this study, We evaluated that our model contains four equilibrium points: the disease-free equilibrium, mono-existent endemic equilibrium 1, mono-existent endemic equilibrium 2, and a disease-endemic equilibrium. In particular, we applied the Routh-Hurwitz criteria to generalize the stability of the equilibria. We also found that the drug-resistant strain prevalence increases when the drug-susceptible strain is vaccinated on time due to the poor quality of the vaccine. We carried out the sensitivity analysis through the partial rank correlation coefficient (PRCC) technique to identify most important parameters. We found that the transmission rate of both strains had the biggest stimulus on disease outbreak. We also demonstrate how vaccination rates affected the equilibrium level of prevalence and found that a proper vaccination program is more effective for reducing two-strain disease burden. Numerical simulations carried out using MATLAB routines to support the analytical conclusions.

Association between ethnic background and COVID-19 morbidity, mortality and vaccination in England: a multistate cohort analysis using the UK Biobank

ObjectivesDespite growing evidence suggesting increased COVID-19 mortality among people from ethnic minorities, little is known about milder forms of SARS-CoV-2 infection. We sought to explore the association between ethnic background...

Modelling the impacts of media campaign and double dose vaccination in controlling COVID-19 in Nigeria

Corona virus disease (COVID-19) is a lethal disease that poses public health challenge in both developed and developing countries of the world. Owing to the recent ongoing clinical use of COVID-19 vaccines and non-compliance to COVID-19 health protocols, this study presents a deterministic model with an optimal control problem for assessing the community-level impact of media campaign and double-dose vaccination on the transmission and control of COVID-19. Detailed analysis of the model shows that, using the Lyapunov function theory and the theory of centre manifold, the dynamics of the model is determined essentially by the control reproduction number (Rmv). Consequently, the model undergoes the phenomenon of forward bifurcation in the absence of the double dose vaccination effects, where the global disease-free equilibrium is obtained whenever Rmv≤1. Numerical simulations of the model using data relevant to the transmission dynamics of the disease in Nigeria, show that, certain values of the basic reproduction number ((R0≥7)) may not prevent the spread of the pandemic even if 100% media compliance is achieved. Nevertheless, with assumed 75% (at R0=4)) media efficacy of double dose vaccination, the community herd immunity to the disease can be attained. Furthermore, Pontryagin's maximum principle was used for the analysis of the optimized model by which necessary conditions for optimal controls were obtained. In addition, the optimal simulation results reveal that, for situations where the cost of implementing the controls (media campaign and double dose vaccination) considered in this study is low, allocating resources to media campaign-only strategy is more effective than allocating them to a first-dose vaccination strategy. More so, as expected, the combined media campaign-double dose vaccination strategy yields a higher population-level impact than the media campaign-only strategy, double-dose vaccination strategy or media campaign-first dose vaccination strategy.

A fractional derivative modeling study for measles infection with double dose vaccination

This study proposes a novel mathematical framework to study the spread dynamics of diseases. A measles model is developed by dividing the vaccinated compartment into the vaccinated-with-the-first-dose and the-second-dose populations. The model parameters are estimated using the genetic algorithm for measles transmission based on monthly cumulative measles data in Indonesia. The threshold is determined to measure a population’s potential spread of measles. The stability of the equilibria is investigated, and the sensitivity analysis is then presented to find the most dominant parameter on the spread of measles. We extend the classical model into Atangana–Baleanu Caputo (ABC) derivative and consider the effects of the first and second vaccination doses on susceptible and exposed individuals. These outcomes are based on the different fractional parameter values and can be utilized to identify significant disease-control strategies. The yields are graphically exhibited to support our results. The overall finding suggests that taking preventive measures has a significant influence on limiting the spread of measles in the population. Increasing vaccination coverage, in particular, will reduce the number of infected individuals, thereby lowering the disease burden in the population.

Modeling and Optimal Control Analysis Applied to Real Cases of COVID-19 Pandemic with Double Dose Vaccination in Ethiopia

Modeling and Optimal Control Analysis Applied to Real Cases of COVID-19 Pandemic with Double Dose Vaccination in Ethiopia

COVID-19 Booster Dose Coverage and Hesitancy among Older Adults in an Urban Slum and Resettlement Colony in Delhi, India.

The high prevalence of vaccine booster hesitancy, with the concomitant waning of humoral vaccine or hybrid immunity, and the emergence of SARS-CoV-2 variants of concern can accentuate COVID-19 morbidity and mortality. The study objective was to ascertain the COVID-19 vaccination coverage, including the administration of precaution (booster) dose vaccination, among the older population in an urban slum and resettlement colony population in Delhi, India. We conducted a cross-sectional survey in an urban resettlement colony, slum, and village cluster in the Northeast district of Delhi among residents aged ≥50 years. A total of 2217 adults (58.28%) had obtained a COVID-19 booster (precaution) dose vaccine, 1404 (36.91%) had received two doses of a COVID-19 vaccine without booster dose, 121 (3.18%) were unvaccinated, while 62 (1.63%) participants received a single dose. Based on adjusted analysis, older adults (>65 years), higher education, and higher per-capita income were statistically significant predictors of booster dose vaccination. More than four in ten adults in an urban slum and resettlement colony in Delhi lacked COVID-19 booster dose vaccination despite high rates of double-dose vaccination (~95%). Public health programming should provide an enhanced focus on reducing complacency with renewed prioritization for improving ease of access to COVID-19 vaccination services, particularly in underserved areas.

Clostridium perfringens epsilon prototoxin mutant rpETXY30A/Y71A/H106P/Y196A as a vaccine candidate against enterotoxemia

Epsilon toxin (ETX) is secreted by Clostridium perfringens (C. perfringens)as a relatively inactive prototoxin (pETX), which is enzymatically activated to ETX by removing carboxy-terminal and amino-terminal peptides. Genetically engineered ETX mutants have been shown to function as potential vaccine candidates in the prevention of the enterotoxemia caused by C. perfringens. In the present study, two recombinant site-directed mutants of pETX, rpETXY30A/Y71A/H106P/Y196A (rpETXm41) and rpETXY30A/H106P/Y196A/F199E (rpETXm42), were synthesized by mutating four essential amino acid residues (Tyr30, Tyr71, His106, Tyr196 or Phe199). Compared to recombinant pETX (rpETX), both rpETXm41 and rpETXm42 lacked the detectable toxicity in MDCK cells and mice, which suggested that both rpETXm41 and rpETXm42 are sufficiently safe to be vaccine candidates. Despite the fact that rpETXm41 and rpETXm42 were reactogenic with polyclonal antibodies against crude ETX, both single- and double-dose vaccination (Vs and Vd, respectively) of rpETXm41 induced a higher level of IgG titer and protection in mice than that of rpETXm42. Therefore, we selected rpETXm41 for the further study. Sheep received Vs of 150 μg rpETXm41 developed significant levels of toxin-neutralizing antibodies persisting for at least 6 months, which conferred protection against crude ETX challenge without microscopic lesions. These data suggest that genetically detoxified rpETXY30A/Y71A/H106P/Y196A could form the basis of a next-generation enterotoxemia vaccine.