vaccine

The development of COVID-19 vaccines with high efficacy has given people hope to overcome the pandemic. However, the increasing number of reports of side effects could affect the number of people who are adherent to vaccination. In most cases, pain, fever, and fatigue have been reported, which is the normal side effect of many vaccines. More serious side effects have also been reported, such as Guillain-Barre syndrome, thrombotic thrombocytopenia, anaphylaxis, and death. Although these side effects seem to be lethal, they are rare, and vaccination is the most efficient strategy to overcome this disease.

The new coronavirus disease (COVID-19) pandemic is a global health problem that appeared in late 2019 through severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This perplexing virus has a high infection rate, and with no specific treatment, the mortality and morbidity rates are rapidly increasing. Moreover, the new virus variant, which is more contagious and has a higher mortality rate than previous variants, has been detected in the United Kingdom. There are few vaccines at clinical stages. However, the distancing, track, and trace will stay with us for at least the next few years. Hence, detecting symptomatic and asymptomatic patients through accurate detective tests such as molecular and serological assays and quarantine is the only preventive method that can be used for controlling the pandemic. It is essential to use highly accurate tests to decrease the number of false negative and false positive results. This research aimed to highlight and critically assess the specificity and sensitivity of coronavirus tests available for detecting the SARS-CoV-2 virus. Currently, this is a multibillion-dollar industry, and many tests enter the clinical setting without having fully been validated.

Toxoplasma gondii is a protozoan parasite with a global distribution. Despite the medical importance of the associated diseases, current therapeutic agents and vaccines are not effective for disease control. Research to find an effective vaccine is ongoing. Attenuated vaccines, particularly those developed through radiation, are promising due to their proper immunogenicity.

The current study aimed to investigate gamma radiation-attenuated tachyzoites of the T. gondii RH strain as a potential vaccine.

Tachyzoites of the RH strain of T. gondii were exposed to gamma rays at doses of 50, 100, and 200 Gy. Tachyzoite viability was assessed using flow cytometry, and infectivity was assessed in HeLa cell cultures. An in vivo study was conducted by injecting the irradiated tachyzoites into BALB/c mice. Disease progression in inoculated mice was compared to a control group by challenging them with intact tachyzoites of the RH strain. Serum levels of interleukins 2 and 10, and interferon-gamma were measured before and after the vaccine challenge.

Flow cytometry showed significant mortality rates in tachyzoites exposed to gamma rays, with 35.28%, 58.31%, and 89.28% mortality at 50, 100, and 200 Gy, respectively. In HeLa cell cultures, gamma ray exposure significantly reduced tachyzoite load compared to controls (P < 0.05). In vivo , mice infected with 50 Gy irradiated tachyzoites showed complete mortality within 14 days, while the 100 Gy group had partial mortality (4 out of 20 died), and the 200 Gy group had full survival. Control mice infected with intact tachyzoites died within 8 days (average survival: 6.8 ± 0.44 days). ELISA results indicated significant increases in cytokine levels (IL-2, IL-10, IFN-γ) in mice treated with 100 Gy and 200 Gy irradiated tachyzoites post-vaccine challenge (P < 0.05). Survival rate monitoring post-vaccine challenge revealed higher survival rates in the 100 Gy and 200 Gy groups compared to controls.

The findings of the current study provide significant insights into the potential use of gamma radiation to reduce the pathogenicity of T. gondii and enhance the immune response in infected hosts. Further research is needed to explore their full potential and safety in human populations.

Vaccine adjuvants are components that enhance immune responses to an antigen. Given the importance of adjuvants, research on novel adjuvants with higher efficacy and fewer adverse effects remains crucial. Spirulina (Arthrospira sp.), an aqueous, photosynthetic, filamentous, spiral, multicellular microalga also classified as a cyanobacterium, is well known for its high protein content, vitamins, essential fatty acids, and amino acids. Cphycocyanin (C-PC) is one of the most significant proteins in Spirulina.

This study aimed to investigate the adjuvant capabilities of three Spirulina-derived substances—Spirulina extract, C-phycocyanin (C-PC), and phycocyanobilin (PCB)—in conjunction with the Hepatitis B surface antigen (HBsAg).

Vaccine groups received the vaccine and adjuvants three times at two-week intervals, administered either orally or by injection in encapsulated or naked forms. To use the injectable form while preventing antigenic effects from the C-PC protein portion, the PCB portion was isolated and used as an injectable adjuvant.

The highest levels of interferon gamma (IFN-γ) and interleukin 4 (IL-4) stimulation were observed in the naked PCB form with the vaccine. In both oral and injectable forms of PCB and C-PC, results indicated an increased expression of Hepatitis B surface antibodies (HBsAb) in response to the antigen. The absence of a significant difference between C-PC and Spirulina extract in oral form suggested that the adjuvant effect of this microalga was primarily due to the C-PC compound. Additionally, the injectable form of PCB led to the highest HBsAb expression level. This enhancement of the humoral immune response indicated that these compounds have potential as adjuvants in both oral and injectable forms.

These findings suggest the potential for improved Hepatitis B vaccine efficacy with this novel adjuvant, paving the way for further evaluation with other vaccines.

According to the literature, COVID-19 vaccines reduce long COVID-19 symptoms such as cognitive dysfunction, kidney diseases, myalgia, and sleeping disorders (5-7). Therefore, the results of the meta-analysis support the clinical safety and efficacy of SARS-CoV-2 vaccines against long COVID-19. However, the available studies have several limitations: 1) there were individuals that exhibited natural improvement of long COVID-19 symptoms which may have been underestimated as vaccination in clinical setting; 2) studies used wide range of COVID-19 vaccines including both inactivated vaccines and mRNA COVID-19 vaccines. Thus, findings should be interpreted with caution. Since booster vaccines show great promise in both prevention of infection and progression, further research on boosters and omicron-specific vaccination is needed to be performed. Consequently, the current comprehensive literature recommends SARS-CoV-2 vaccine to reduce the risk of long COVID-19 in cases of progression. There are no findings of a negative effect of COVID-19 vaccination on worsening symptoms of COVID-19. Therefore, SARS-CoV-2 vaccination should be improved as soon as possible, especially offering a full course of vaccination. More research is needed to discover the mechanism of action of the COVID-19 vaccines on long COVID-19 in the future.

Despite the availability of vaccines, measles has remained a significant health threat, with recent global surges in cases. This study focused on factors influencing measles vaccine compliance in barangay C, Northern Mindanao, Philippines. It aimed to identify barriers to compliance and assess differences in compliance levels based on demographic factors like age, decision-maker, and educational attainment. 

This study utilized a non-experimental quantitative descriptive design to examine factors influencing measles vaccination compliance among residents of barangay C. The study data were collected using a structured survey questionnaire that served as the instrument designed to measure compliance across psychosocial factors and behavioral-specific cognitions. The sample comprised 132 respondents aged 18 to 59 who met the inclusion criteria. Statistical analyses, including the t-test and ANOVA/F-tests, were employed to evaluate significant differences in vaccination compliance when grouped by age, family decision-makers, and educational attainment. Results highlighted group-specific variations in compliance, emphasizing psychosocial and behavioral determinants, with significance levels determined at P<0.05.

Younger adults showed higher compliance with psychosocial factors (mean: 3.50) compared to middle-aged adults (mean: 3.42), while middle-aged adults exhibited higher compliance with behavioral-specific cognitions (mean: 3.42). However, t-test revealed no significant differences in compliance levels based on age (P=0.834 for psychosocial factors and P=0.675 for behavioral-specific cognitions). Among decision-makers, mothers exhibited the highest compliance with psychosocial factors (mean: 3.57), and this difference was statistically significant (P=0.029). No significant differences were found in compliance levels based on educational attainment, with P=0.714 for psychosocial factors and P=0.863 for behavioral-specific cognitions.

No significant differences were found based on age and educational attainment; the study underscores the importance of decision-makers, particularly mothers, in shaping vaccination behaviors. These insights suggest that vaccination programs could benefit from improving psychosocial factors and addressing the specific needs of decision-makers, thereby promoting higher compliance with vaccination recommendations.

Knowledge, attitude, practices, and concerns (KAPC) are important components for the COVID-19 vaccine. Identifying the typology of KAPC can provide health care professionals insight into ways to encourage vaccination uptake among the student population. The study pursues two specific objectives: Classification of Mazandaran University of Medical Sciences students based on KAPC about the COVID-19 vaccine, determining the relationship between these patterns, and performing COVID-19 vaccine injection.

A cross-sectional study design was used to collect the data about the students’ COVID-19 vaccination and their perception of KAPC toward the COVID-19 vaccine. The analysis of data was conducted in two steps. First, we conducted a latent profile analysis (LPA) to identify subgroups of the COVID-19 vaccine KAPC patterns. Second, the associations between the typology of KAPC and vaccine injection were assessed by logistic regression analysis. Also, the scores of KAPC were compared using an analysis of variance and Bonferroni post hoc tests.

The current study showed three profiles (patterns) of the COVID-19 vaccine KAPC. These patterns included “moderate to high for KAPC” (profile 1: 70.5%), “high knowledge, attitude, practices, and low concerns” (profile 2: 25.4%), “moderate knowledge and low attitude, practices, and high concerns” (profile 3: 4.1%). Students in the three profiles differed significantly in their KAPC factors. The individuals with membership in profile 2 and profile 3 relative to profile 1 have 73% and 99% less odds of injecting the vaccine, respectively.

The patterns of KAPC have various distributions in vaccine injection. It seems that governmental authorities should take measures to improve the knowledge, attitude, and practice of the people appropriate to each profile and identify any obstacles to their promotion.

COVID-19 infection during pregnancy could be associated with placental histopathological changes such as vascular diseases and malperfusion. There are studies showing that mRNA vaccines are not associated with significant placental pathological changes. Our objective was to evaluate the placental histopathology in pregnant women who received Sinopharm, an inactivated virus vaccine, during pregnancy.

The study included placental samples collected from mothers who gave birth of living singletons through elective cesarean sections performed between March 2022 and May 2022 at Imam Khomeini Hospital Complex. The study included women who had no history of positive reverse transcription polymerase chain reaction (RT-PCR) testing for COVID-19 during pregnancy, and had received at least one dose of COVID-19 vaccine during their pregnancy. Humoral levels of anti-SARS-CoV-2 spike IgG were measured in both the mothers and neonates.

The study included 20 mother-neonate pairs. The mean maternal age was 34±3.6 years, and all mothers received Sinopharm vaccine as their first and second doses. The last vaccine dose was administered during pregnancy, with 3 mothers receiving it in the first trimester, 9 in the second trimester, and 8 in the third trimester. The histopathological findings in the placental samples included decidual vasculopathy, subchorionic thrombosis, and chronic histiocytic intervillositis. All mothers and neonates, except one pair, were positive for anti-spike antibody.

Multiple abnormal histopathological findings were reported in placenta of vaccinated mothers. However, similar to previous studies, these placental findings are considered mild lesions and have been observed in both vaccinated and unvaccinated mothers.

Gonadotropin hormone-releasing hormone (GnRH) is a peptide involved in mammals’ fertility and may also serve as a candidate target for cancer immunotherapy. Immunonsterilization is known as a proper alternative to surgical castration and has been advocated by European countries in recent years. Immunization with GnRH can effectively inhibit the secretion of gonadotropins and cause infertility in both genders of mammals. In this study, a recombinant trimer of GnRH is designed and expressed in a prokaryotic system.  A construct containing GnRH trimer was designed and prepared using gene synthesis. A cloning site was embedded and connected to the GnRH using a linker to further clone any protein of interest. The construct was subcloned into a pET-32a+ plasmid vector. The recombinant vector was transferred to BL21, an Escherichia coli strain, and the expression was induced using isopropyl β- d-1-thiogalactopyranoside (IPTG). The cell lysate was prepared using lysis buffer and nickel affinity chromatography purification. The GnRH expression was evaluated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis after protein purification. The cloning was verified using a polymerase chain reaction (PCR) followed by sequencing the recombinant vector. The result of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis verified the recombinant protein’s expression and the purification process’s function. The GnRH was properly cloned and expressed in BL21. The results also verified the reliability of the purification process. The construct design allows the researchers to express another peptide sequence attached to the GnRH using the embedded linker to improve the stability and antigenicity. A stable recombinant GnRH would be applied in immunocastration and cancer immunotherapies.

Investigating re-infection with COVID-19 is necessary due to the existence of genetic differences among populations after a general vaccination plan. In addition to genetic differences, gender, age, the presence of underlying diseases, and the type of vaccine are factors that affect the rate and severity of re-infection after vaccination.

Demography, physical activity and nutrition, underlying diseases, the period of involvement with the COVID-19 pandemic, and the percentage of re-infection before and after each stage of vaccination of the medical staff at Imam Khomeini Hospital in Ardabil (Iran) were evaluated. Our study was performed in a descriptive-analytical manner among 149 healthcare workers. The data were collected using a valid and reliable questionnaire and analyzed using SPSS version 26.

According to the results, 69.1% of healthcare workers had a positive PCR test or symptoms of COVID-19 before the first injection of the vaccine. The types of injected vaccines included AstraZeneca, Sinopharm, Sputnik V, Bharat, Barekat, Spicogen, and PastoCovac. After the injection of the first dose of the vaccine, the number of severe cases decreased from 30.9% to 10.7%, which indicates the effectiveness of the vaccination.

The lowest rate of re-infection was observed in people with good physical activity compared to those who were less active (9.6% versus 59.6%). The highest rate of re-infection with COVID-19 between the first and second doses of the vaccine was related to Sinopharm, Sputnik V, and AstraZeneca. The highest rate of re-infection (82.7%) was in the age group under 40 years old.

Since the beginning of the COVID-19 pandemic, vaccination has been crucial in reducing deaths and hospitalizations. However, vaccination may trigger autoimmune responses. We present the first case of new-onset systemic lupus erythematosus in a 12-year-old girl, three weeks after receiving the first dose of Sinopharm BIBP COVID-19 vaccine. Complications of COVID-19 vaccines are typically mild. There have been reports of a potential association between the vaccines and autoimmune disorders. However, severe events are rare. Vaccination for COVID-19 is recommended even for those with a genetic predisposition to autoimmune disease, as the advantages of preventing COVID-19 outweigh the potential risks of acquiring autoimmune diseases.

Vaccine hesitancy extends beyond simple refusal to receive immunizations, encompassing psychological, cultural, and sociodemographic factors that influence individuals’ perceptions and decision-making regarding vaccines.

This study aimed to determine the prevalence and factors influencing COVID-19 vaccine hesitancy among Brazilian immigrants.

A survey targeting Brazilian immigrants in Portugal was conducted from May to August 2020, involving 598 participants. The study explored the relationship between vaccine hesitancy and non-compliance with social distancing measures using a Poisson regression model with robust variance to calculate prevalence ratios (PRs).

The study identified a vaccine hesitancy rate of 15.1% among Brazilian immigrants. Older individuals (aged 50 and above) exhibited a significantly higher hesitancy, with an adjusted prevalence ratio (aPR) of 10.0 (95% CI: 1.8 - 13.6). Those adhering to a religion were 2.3 times more likely to hesitate (95% CI: 1.4 - 3.4), and a reluctance to follow social distancing measures was associated with a 10.4 times higher hesitancy rate (95% CI: 4.2 - 15.4). Highlighting these correlations is vital for developing strategies to enhance vaccine acceptance and tackle public health challenges.

There is a notable rate of COVID-19 vaccine hesitancy among Brazilian immigrants in Portugal, significantly influenced by age, religious practice, and non-adherence to social distancing measures. Implementing targeted educational and awareness programs is recommended to reduce hesitancy and improve vaccine coverage within this community and in similar settings.