COVID-19 Vaccines over Three Years after the Outbreak of the COVID-19 Epidemic.

The outbreak of COVID-19 started in December 2019 and spread rapidly all over the world. It became clear that the development of an effective vaccine was the only way to stop the pandemic. It was the first time in the history of infectious diseases that the process of the development of a new vaccine was conducted on such a large scale and accelerated so rapidly. At the end of 2020, the first COVID-19 vaccines were approved for marketing. At the end of March 2023, over three years after the outbreak of the COVID-19 pandemic, 199 vaccines were in pre-clinical development and 183 in clinical development. The candidate vaccines in the clinical phase are based on the following platforms: protein subunit, DNA, RNA, non-replication viral vector, replicating viral vector, inactivated virus, virus-like particles, live attenuated virus, replicating viral vector combined with an antigen-presenting cell, non-replication viral vector combined with an antigen-presenting cell, and bacterial antigen-spore expression vector. Some of the new vaccine platforms have been approved for the first time for human application. This review presents COVID-19 vaccines currently available in the world, procedures for assurance of the quality and safety of the vaccines, the vaccinated population, as well as future perspectives for the new vaccine platforms in drug and therapy development for infectious and non-infectious diseases.

Application of loop-mediated isothermal amplification combined with colorimetric and lateral flow dipstick visualization as the potential point-of-care testing for Corynebacterium diphtheriae.

BACKGROUND: Diphtheria outbreaks occurred in endemic areas and imported and indigenous cases are reported in UE/EEA. Because of the high infectiveness and severity of the disease, early and accurate diagnosis of each suspected case is essential for the treatment and management of the case and close contacts. The aim of the study was to establish simple and rapid testing methods based on Loop-Mediated Isothermal Amplification (LAMP) assay for the detection of Corynebacterium diphtheriae and differentiation between toxigenic and non-toxigenic strains. METHODS: Corynebacterium diphtheriae and Corynebacterium ulcerans isolates from the National Institute of Public Health-National Institute of Hygiene collection were used for the development of LAMP assay for the diagnosis of diphtheria and nontoxigenic C. diphtheriae infections. Various colorimetric methods for visualization of results were investigated. Sensitivity and specificity of the assay were examined using a collection of DNA samples from various gram-positive and gram-negative bacteria. RESULTS: The LAMP assay for tox and dtxR genes was developed. The sensitivity and specificity of the assay were calculated as 100%. The detection limit was estimated as 1.42 pg/µl concentration of DNA template when the reaction was conducted for 60 min. However, the detection limit was lowered 10 times for every 10 min of reduction in the time of incubation during the reaction. Positive results were successfully detected colorimetrically using hydroxynaphthol blue, calcein, QuantiFluor, and lateral flow Milenia HybriDetect dipsticks. CONCLUSION: The assay developed in the study might be applied for point-of-care testing of diphtheria and other C. diphtheriae infections as well as for other infections caused by diphtheria-toxin producing Corynebacterium species. It is highly sensitive, specific, inexpensive, easy to use, and suitable for low-resource settings.

Isothermal DNA amplification combined with lateral flow dipsticks for detection of biothreat agents.

The recently developed methods of nucleic acids isothermal amplification are promising tools for point-of-care diagnostics and in the field detection of pathogenic microorganisms. However, application of these methods outside a laboratory faces some challenges such as the rapid and sensitive detection of amplified products and the absence of cross-reactivity with genetically related microorganisms. In the presented study we compared three methods of isothermal DNA amplification loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA) and thermophilic helicase-dependent isothermal DNA amplification (tHDA), for detection of highly dangerous pathogens, such as Bacillus anthracis, Francisella tularensis and Yersinia pestis, and combined them with lateral flow dipsticks for the rapid visualization of amplified products. We observed low specificity of the three methods for B. antharcis, medium for Y. pestis and high for F. tularensis detection. Sensitivity and the detection limit were high and comparable for all the methods. We concluded that the lateral flow dipsticks have been a very useful tool for product detection of the isothermal amplification methods and enable reading the results without the use of any equipment. However, our results showed that the use of isothermal amplification methods is strongly related to the risk of false positive results.

Changes in MLST profiles and biotypes of Corynebacterium diphtheriae isolates from the diphtheria outbreak period to the period of invasive infections caused by nontoxigenic strains in Poland (1950-2016).

BACKGROUND: Corynebacterium diphtheriae is a re-emerging pathogen in Europe causing invasive infections in vaccinated persons and classical diphtheria in unvaccinated persons. In the presented study we analysed genetic changes in C. diphtheriae isolates collected in Poland from the period before the introduction of the mass anti-diphtheria vaccination to the present time when over 98% of the population is vaccinated. METHODS: A total of 62 C. diphtheriae isolates collected in the 1950s-1960s, 1990s and 2000-2016 in Poland were investigated. Examined properties of the isolates included toxigenic status, presence of tox gene, biotype, MLST type (ST) and type of infection. RESULTS: A total of 12 sequence types (STs) were identified among the analysed C. diphtheriae isolates. The highest variability of STs was observed among isolates from diphtheria and asymptomatic carriers collected in the XX century. Over 95% of isolates collected from invasive and wound infections in 2004-2016 belonged to ST8. Isolates from the XX century represented all four biotypes: mitis, gravis, intermedius and belfanti, but the belfanti biotype appeared only after the epidemic in the 1990s. All except three isolates from the XXI century represented the biotype gravis. CONCLUSIONS: During a diphtheria epidemic period, non-epidemic clones of C. diphtheriae might also disseminate and persist in a particular area after the epidemic. An increase of the anti-diphtheria antibody level in the population causes not only the elimination of toxigenic strains from the population but may also influence the reduction of diversity of C. diphtheriae isolates. MLST types do not reflect the virulence of isolates. Each ST can be represented by various virulent variants representing various pathogenic capacities, for example toxigenic non-invasive, nontoxigenic invasive and nontoxigenic non-invasive.

[Susceptibility of Lactobacillus rhamnosus strains isolated from probiotic products to antimicrobial agents]. / Lekowrazliwosc szczepów Lactobacillus rhamnosus wyizolowanych z produktów probiotycznych.

INTRODUCTION: Probiotics Generally Recognized as Safe (GRAS), when given in relevant dose, are able to induce strain-specific beneficial effects for health of humans or animals. METHODS: L. rhamnosus strains originating from four medicinal products, 2 dietary foods for special medical purposes and dietary supplement, were tested for susceptibility to antibiotics and chemotherapeutics following L. rhamnosus and L.rhamnosus GG strain identity confirmation with use of PCR, rep-PCR and AFLP methods. RESULTS AND CONCLUSIONS: L. rhamnosus working seeds of medicinal products and isolates originating from dietary foods for special medical purposes or dietary supplement were found correctly classified on the levels of species or L. rhamnosus GG strain identities. Antibiotics and chemotherapeutics susceptibility profiles of L. rhamnosus strains allowed for choice of treatment options in six out of seven products under study.

Effect of different Bacillus Calmette-Guerin substrains on growth inhibition of T24 bladder cancer cells and cytokines secretion by BCG activated peripheral blood mononuclear cells of PBMCs.

BACKGROUND: Bladder carcinoma is the most common malignancy of the urinary tract. Approximately 75-85% of patients present non-muscle invasive bladder cancer (NMIBC). Standard primary treatment for NIMBC is transurethral resection (TUR) followed by intravesical Bacillus Calmette-Guerin (BCG) immunotherapy. BCG has been accepted as the most effective agent in clinical use against NMIBC. Various BCG substrains are used worldwide for bladder cancer immunotherapy although the impact of used BCG substrain on BCG antitumor capacity is a little investigated. OBJECTIVES: The aim of this study was to compare the antitumor capacity and the ability to trigger cytokines production of three BCG substrains by stimulation of the local innate immunity in vitro. MATERIAL AND METHODS: The human bladder cancer cell line T24 was co-cultured with each of the BCG substrains: Moreau, Tice and RIVM alone or with BCG pretreated DCs (dendric cells) and allogenic PBMCs derived from the same donor. The inhibition of T24 cell growth was evaluated by 3H-thymidine incorporation. Production of Th1 cytokines (IFN-γ, TNF-α, IL-12) and Th2 cytokines (IL-10, IL-4) was measured in cultures of BCG-activated PBMCs by ELISA test. RESULTS: An approximately two-fold inhibition of T24 cell proliferation was observed as a direct cytotoxic effect of tested BCG substrains on T24 cells. However, BCG inhibited the growth of tumor cells mainly by activating the effector cells of innate immunity. About a 10-fold inhibition of T24 cell proliferation was observed when T24 cells were co-cultured with allogenic BCG pretreated DCs and PBMCs derived from the same donor. The PBMCs activated by compared live BCG substrains secreted large amounts of TNF-α and IFN-γ cytokines. CONCLUSIONS: Tested BCG substrains had little direct inhibitory effect on T24 cell proliferation. Moreau evolutionarily early BCG substrain showed similar strong, indirect antitumor effects as evolutionarily late BCG substrains Tice and RIVM.

[The studies of elimination of nontypeable Haemophilus influenzae strains using the animal model of infection]. / Badania eliminacji nietypowalnych szczepów Haemophilus influenzae na modelu zwierzecym.

INTRODUCTION: The intranasal immunization is considered the effective method to induce immunological response in the mucosa and the model useful to develop the vaccine against otitis media due to nontypaeble Haemophilus influenzae infections. In the study, elimination of NTHi strains isolated from healthy and carrier individuals, varying with several genetic determinants, from mice nasopharynx, lungs and ears tissues and the interactions among strains during mixed infections were evaluated. METHODS: Mice were infected with single and mixture of NTHi strains previously identified as non or potentially invasive. The curves of infections were drown from the averages of log cfu/mg values obtained for nasopharynx or ears leavages or lungs homogenates coupled with standard deviation at each time point using 5 mice. The significance of the differences was confirmed using ANOVA method. RESULTS: The course of infections induced with a single noninvasive or potentially invasive strains in the mice nasopharynx, ear or lung tissues were not found to differ in respect to the level and duration. Regardless the strain used, higher elimination rates in the ear and lung tissues in comparison with nasopharynx were fund. Different rate of elimination was found in the case of mixture infections where the strain, determined in the previous study as potentially invasive, was dominating. CONCLUSION: The concurrence model among not-invasive and potentially invasive NTHi strains in the host niche was thus confirmed using in vivo model of infection.

[Phenotypic and genotypic characterization of probiotic bacterial strains used in medicinal products]. / Fenotypowa i genotypowa charakterystyka probiotycznych szczepów bakteryjnych stosowanych w produktach leczniczych.

INTRODUCTION: The optimization of quality testing strategy of products containing probiotics might allow to general improvement of its safer use in humans. The goal of the study was the evaluation of quality expressed by identity, colony forming unit (CFU) and antibiotic sensitivity ofprobiotics used in medicinal products available in Poland using the appropriate and validated procedures. METHODS: The medicinal products containing L. rhamnosus, L. acidophilus, L. delbrueckii subsp. bulgaricus and B. animalis subsp. lactis, L. helveticus, and L. gasseri were tested for species identity performed with validated rep-PCR (BOXA 1R) method. The antimicrobial susceptibility of working seeds and strains isolated to 26 antibiotics were tested by disk diffusion and E-test methods using relevant references as recommended by EUCAST. The numbers of probiotic strains, expressed as cfu count per package, was done using plating plunge method. RESULTS: All strains tested, except B. lactis, were found to be resistant to trimethoprim-sulphamethoxazole, nalidixic acid, metronidazole, and colistin. B. lactis was resistant to aminoglycosides. L. rhamnosus strains were found to be resistant to vancomycin, (MIC > 256 microg/ml) similarly to ATCC strains (L. rhamnosus GG 53103 and 244). The sensitivity to other antibiotics was strain specific. The rep-PCR method was found species and strain specific. All products tested fulfilled declared countent as measured by cfu count/package. CONCLUSIONS: Quality of medicinal products containing probiotics was found undoubted and confirmed. The optimized strategy of quality monitoring of probiotics used in medicinal products can be used in dietary supplements and foodstuffs intended for particular nutritional uses.

Mechanism of Vipera berus venom activity and the principles of antivenom administration in treatment.

In the present paper, the actual knowledge on the composition and toxic properties of the European common viper venom was analyzed. The organism response to the particular components and the methods of neutralization of venom toxin in bitten person were presented. On the basis of literature data, the clinical course of envenomation with its classification according to the severity of symptoms was characterized. In the paper the situations in which administration of antivenom is required to neutralize toxic properties of venom and its possible adverse reactions were also described.

[Immunization of adolescents and adults as the strategy of improvement of epidemiology of pertussis]. / Szczepienia mlodzieizy i osób doroslych jako strategia poprawy sytuacji epidemiologicznej zachorowan na krztusiec.

Increase of pertussis incidence has been recognised mainly among adolescents and adults since 90. As adolescents and adults sustain the reservoir of infection for non immunized and not completely immunized newborns and neonates, increased rates of pertussis are dangerous. The improvement of pertussis epidemiology might have been obtained through routine immunization of adolescents and adults able to interrupt of B. pertussis circulation in the population. The improvement of surveillance and diagnostics might have result in better detection of the disease in children at the age up to first year and in older age groups.

[Prevalence of anti-HAV antibodies in Warsaw population]. / Poziom przeciwcial przeciwko wirusowemu zapaleniu watroby typu A u osób z terenu Warszawy.

The result of serological survey that was carried out on 895 subjects of Warsaw population at age 1-54 years showed the high proportion of susceptible to hepatitis A infection. It was shown about 90% susceptible among children at age 1-4 years, and about 80% among older children and adolescents aged below 19 years. The low endemicity of hepatitis A in Poland has been observed since 1997 and very low endemicity since 2002. Only 54 hepatitis A cases were reported in 2005. The morbidity was 0.18 per 100,000 habitants. Vaccination against hepatitis A by inactivated vaccine is recommended in Poland for travellers to regions that have high or intermediate endemicity of hepatitis A, for people whose employment includes production or distribution of food as well as for children and adolescents. Prevalence high proportion of susceptibles in population suggests the need of verification of the present recommendations for hepatitis A vaccination.

[HBV genotypes among patients with chronic hepatitis B in the area of central Poland]. / Genotypy HBV u pacjentów z przewleklym zapaleniem watroby typu B z terenu centralnej Polski.

At present, eight (8) HBV genotypes have been identified, marked by letters from A to H. The distribution of particular genotypes , both in the world and in Poland, is the focus of particular epidemiological interest as well as its possible association with therapeutic efficacy of patients with chronic hepatitis B (CHB) undergoing antiviral therapy. The goal of the study was HBV genotype determination among patients with CHB living in the area of central Poland. There were 65 patients (18 females and 47 males) aged 18-80 years (mean: 42.3). All of the patients had HBsAg detectable for at least 6 months and previously they did not receive any antiviral or immunomodulating therapy. HBV genotyping was performed by means of commercial method "INNO LiPA Genotyping". Genotype A was found in 56 out of 65 (86.6%) patients, genotype D in 6 out of 65 (9.2%), and mixed genoptype A+D was found in 3 out of 65 (4.6%) patients. HBeAg was detected in 49 out of 56 (87.5%) persons with genotype A, in 4 out of 6 persons with genotype D and in one person with mixed genotype A+D. Mixed genotype A+D was found only among males. Anti-HBe was found exclusively among 6 out of 56 (10.7%) persons with genotype A. Both HBeAg and anti-HBe were undetectable in one person with genotype A, in 2 persons with genotype D and in 2 persons with mixed genotype A+D. The method applied for this study is particularly suitable for the determination of mixed HBV genotypes, as well as for clinical or epidemiological studies of a large numbers of samples. Future studies to be performed after an antiviral or other form of therapy in patients with CHB may bring some evidence on the influence of treatment in relation to HBV genotype. Further studies on HBV genotypes distribution in different regions of the country may allow to gather data on molecular epidemiology of HBV infection in Poland.