Understanding the time-driven shifts of vaccine effectiveness against any and severe COVID-19 before and after the surge of Omicron variants within 2.5 years of vaccination: A meta-regression

OBJECTIVES

The COVID-19 pandemic required rapid development of vaccines within a short period of time which did not allow to assess vaccine effectiveness (VE) in the long-term.

METHODS

A computerized literature search was undertaken to identify eligible studies, with no language restrictions, published between 1 December 2020 and 30 June 2023.

RESULTS

Out of a total of 27,597 publications, 761 studies were included. Early VE of 87.2% decreased to 55.1% after 9 months among populations fully immunized not only with mRNA (proxy mRNA) vaccines, and 66.3% decreased to 23.5% in populations immunized exclusively with non-mRNA vaccines. Protection against severe COVID-19 declined to 80.9% for proxy mRNA vaccines and 67.2% for non-mRNA vaccines. Omicron variants significantly diminished VE. Within 6-8 months of receiving a single booster of an mRNA vaccine, VE declined to 14.0% and 67.7% for any and severe COVID-19, respectively. Multiple mRNA booster doses restored protection that declined to 29.5% and 70.6% for any and severe COVID-19, respectively, within 5-7 months.

CONCLUSION

Outcomes of this meta-regression underscore the evolving nature of COVID-19 in response to vaccination, dosing schedules, and emerging variants, and provide crucial insights for public health interventions and vaccination strategies.

Risk factors affecting COVID-19 vaccine effectiveness identified from 290 cross-country observational studies until February 2022: a meta-analysis and meta-regression

BACKGROUND

Observational studies made it possible to assess the impact of risk factors on the long-term effectiveness of mRNA and adenoviral vector (AdV) vaccines against COVID-19.

METHODS

A computerized literature search was undertaken using the MEDLINE, EMBASE, and MedRxiv databases to identify eligible studies, with no language restrictions, published up to 28 February 2022. Eligible were observational studies assessing vaccine effectiveness (VE) by disease severity with reference groups of unvaccinated participants or participants immunized with one, two, or three vaccine doses. Our study was carried out in compliance with the PRISMA and MOOSE guidelines. The risk of study bias was identified using the Newcastle-Ottawa Quality Assessment Scale. The GRADE guidelines were applied to assess the strength of evidence for the primary outcome. The synthesis was conducted using a meta-analysis and meta-regression.

RESULTS

Out of a total of 14,155 publications, 290 studies were included. Early VE of full vaccination against COVID-19 of any symptomatology and severity decreased from 96% (95% CI, 95-96%) for mRNA and from 86% (95% CI, 83-89%) for AdV vaccines to 67% for both vaccine types in the last 2 months of 2021. A similar 1-year decline from 98 to 86% was found for severe COVID-19 after full immunization with mRNA, but not with AdV vaccines providing persistent 82-87% effectiveness. Variant-reduced VE was only associated with Omicron regardless of disease severity, vaccine type, or vaccination completeness. The level of protection was reduced in participants aged >65 years, with a comorbidity or those in long-term care or residential homes independently of the number of doses received. The booster effect of the third mRNA dose was unclear because incompletely restored effectiveness, regardless of disease severity, declined within a short-term interval of 4 months.

CONCLUSIONS

Full vaccination provided an early high, yet waning level of protection against COVID-19 of any severity with a strong impact on the high-risk population. Moreover, the potential risk of new antigenically distinct variants should not be underestimated, and any future immunization strategy should include variant-updated vaccines.

Clinical and demographic characteristics of psychiatric patients seropositive for Borrelia burgdorferi

Purpose.

Borrelia burgdorferi (Bb) infection can affect the central nervous system and possibly lead to psychiatric disorders. We compared clinical and demographic variables in Bb seropositive and seronegative psychiatric patients and healthy controls.

Method.

Nine hundred and twenty-six consecutive psychiatric patients were screened for antibodies to Bb and compared with 884 simultaneously recruited healthy subjects.

Results.

Contrary to healthy controls, seropositive psychiatric patients were significantly younger than seronegative ones. None of the studied psychiatric diagnostic categories exhibited stronger association with seropositivity. There were no differences between seropositive and seronegative psychiatric patients in hospitalization length, proportion of previously hospitalized patients and proportion of subjects with family history of psychiatric disorders.

Conclusion.

These findings elaborate on potential association between Bb infection and psychiatric morbidity, but fail to identify any specific clinical ‘signature’ of Bb infection.

Lyme borreliosis infection as a cause of dilated cardiomyopathy

The relatively low percent of patients affected with the cardiac form of Lyme borreliosis is difficult to diagnose, especially if the disease manifests itself in ways other than atrio-ventricular blockade. The advanced stage of Lyme carditis manifesting as dilated cardiomyopathy is a special case of this affliction. The authors of this report present clinical experience with an attempt to support the working hypothesis about involvement of Lyme borreliosis infection in the development of dilated cardiomyopathy. The patients were clinically examined thoroughly with special attention to the cardiovascular system. In addition to the basic clinical methods, the following procedures have been employed: dynamic Holter's electrocardiography, exercise ECG test, coronarography, and myocardial biopsy. From laboratory methods pertaining to the detection of Borrelia, ELISA method, Western blot, PCR, electron microscopy and histopathological analysis were used. In all three cases, clinical and laboratory findings provided the evidence of the borreliosis infection involvement in the development of dilated cardiomyopathy.

Lyme borreliosis--waiting for Lyme carditis? A long-term prospective study

A long-term prospective study of patients with confirmed non-cardiac form of Lyme disease (n=221) over a mean follow-up period of 40.6 months is reported. The study revealed no case of Borrelia-related cardiac involvement developed after several years in patients who had received antibiotic therapy in the early period. Therefore, these patients do not need follow-up by a cardiologist.

Study of awareness of tick-borne diseases among children and young people in the Czech Republic

In the 2000 and 2001 years, there was performed a study which has given some insight on the knowledge of youths about ticks and tick-borne diseases. Two thousand seven hundred and sixty-three respondents from 6 to 26 years of age took part in this investigation. More than 98% of respondents knew about the existence of ticks. Almost 93% of children and 97% of adolescents reported that ticks feed on blood. Although the majority of respondents aged 10 to 26 years is convinced that ticks live on vegetation, 23% of them supposed that ticks jump on humans from trees. As many as 93.5% of youths knew that Lyme disease is transmitted by ticks. The main sources of information about Lyme disease for students and pupils older than 10 years of age are television and radio (40.9%) and the press (37.5%). The frequency of contact of young people with ticks is high--90.4% of children younger than 12 years, and 93.7% of youths from 10 to 26 years of age had at least once an attached tick. 56.1% of youths older than 10 years use oil to remove an attached tick. Almost 23.7% remove ticks with bare hands. People used those methods of tick removal although even children younger than 12 years of age knew that it was an incorrect habit. After removing, a tick is most frequently burned.

Higher prevalence of antibodies to Borrelia burgdorferi in psychiatric patients than in healthy subjects

OBJECTIVE

Borrelia burgdorferi infection can affect the CNS and mimic psychiatric disorders. It is not known whether Borrelia burgdorferi contributes to overall psychiatric morbidity. The authors compared the prevalence of antibodies to Borrelia burgdorferi in groups of psychiatric patients and healthy subjects to find out whether there is an association between this infection and psychiatric morbidity.

METHOD

Between 1995 and 1999 the authors screened for antibodies to Borrelia burgdorferi in 926 psychiatric patients consecutively admitted to Prague Psychiatric Center. They compared the results of this screening with findings from 884 consecutive healthy subjects who took part in an epidemiological survey of antibodies to Borrelia burgdorferi in the general population of the Czech Republic. Sera were tested by means of enzyme-linked immunosorbent assay. Circulating immune complexes were isolated by polyethylene glycol precipitation. To control for potential confounders, the two groups of patients and healthy subjects were matched according to gender and age. Results were obtained in a sample of 499 matched pairs.

RESULTS

Among the matched pairs, 166 (33%) of the psychiatric patients and 94 (19%) of the healthy comparison subjects were seropositive in at least one of the four assays.

CONCLUSIONS

These findings support the hypothesis that there is an association between Borrelia burgdorferi infection and psychiatric morbidity. In countries where this infection is endemic, a proportion of psychiatric inpatients may be suffering from neuropathogenic effects of Borrelia burgdorferi.

[Prevalence of antiborrelia antibodies in two populations: various interpretations of the same data]

OBJECTIVE

The objective of the work was to test whether differently formulated hypotheses, when using correct statistical methods, and the same data lead to the same results. The work pertains to the interpretation of the prevalence of antiborrelia antibody levels in more or less high risk populations.

GROUP

A group of 200 blood donors from Prague (100 men, mean age 33.5 years and 100 women mean age 24.4 years) and 71 subjects with a higher risk of contact with ticks infected with Borrelia burgdorferi--forestry workers from the Sumava mountains (39 men, mean age 40.6 years and 32 women, mean age 44.5 years).

METHOD

In all participants antiborrelia antibodies class IgM and IgG were assessed and using the Western blot method the presence of specific antigens was examined. The blood samples of all probands were analyzed in the national reference laboratory for Lyme borreliosis CEM in the National Institute of Public Health in Prague. To test the hypothesis on the difference of groups as regards the frequency of positive antibody levels the chi square test was used. For testing the hypothesis on the difference of the groups as regards antibodies irrespective of normal laboratory values the non-parametric method--the Mann-Whitney test was used.

RESULTS

The group of Prague blood donors and forestry workers from the Sumava mountains do not differ as to the individual frequency of positive antibody values assessed by the ELISA method in class IgM and IgG but they differ in class IgM assessed by the Western blot method. Both groups differ moreover markedly in the general distribution of antibodies unrelated to normal laboratory values assessed by the ELISA method in class IgM, in class IgG the distribution does not differ.

CONCLUSION

We provided evidence that when using a different formulation of the hypothesis while using correct statistical methods identical data can be differently interpreted. Thus in the interpretation of the prevalence of antiborrelia antibody levels in healthy populations with a different risk--even if the two groups do not differs as to the frequency of positive findings, there is a significant statistical difference in their distribution.

[Culture of Borrelia burgdorferi sensu lato from patients in the Czech Republic]

Spirochete of Borrelia burgdorferi sensu lato were isolated in a modified BSK medium from 26 patients of 275 investigated suffering from early and late borreliosis. The isolates were specified by phenotype and genotype analysis using monoclonal antibodies, by immunochemical methods and by including species specific 16S rRNA, OspA and OspC primers and probes in a polymerase chain reaction with hybridization. Borrelia afzelii was found in 9 patients, Borrelia garinii in 16 and B. burgdorferi sensu stricto in one instance. B. afzelii was isolated from 5 biopsies with erythema migrans. 2 with acrodermatitis chronica atrophicans and from blood of 2 patients with arthritis. B. garinii cultures were prepared from 6 cerebrospinal fluids, 3 blood samples, 1 placenta, 1 liver biopsy and 5 skin samples. Unique was B. burgdorferi detected in a bioptic sample of the heart muscle which was positive on immunohistochemical examination. Monoclonal antibodies against OspA and genotype analysis provided evidence that Borrelia garinii isolates from cerebrospinal fluid are close to serotype IV. One CSF isolate was resistant to antibiotics; the tropism of B. garinii to nervous tissue is contemplated.

Sensitivity of Borrelia burgdorferi strains isolated in the Czech Republic

We tested in vitro susceptibility of 5 strains of Borrelia burgdorferi sensu lato, isolated from patients in the Czech Republic, to penicillin G, ceftriaxone, cefotaxime, doxycycline and amoxycillin combined with clavulanic acid by broth macrodilution method on BSK medium. Results confirmed high efficacy of the tested drugs, particularly on B. afzelii and B. burgdorferi sensu stricto. A strain of B. garinii, isolated from cerebrospinal fluid, required a longer period of antibiotic activity before inhibitory effects were achieved. Penicillin G was effective only in higher concentrations, attainable by i. v. application. Ceftriaxone had the strongest borreliacidal activity.

[Informational value of the prevalence of antiborrelia antibodies in a healthy and at risk population]

The authors tried to confirm data on the prevalence of antiborrelia antibodies class IgM and IgG in the local healthy population (200 blood donors) and in subjects with an increased risk of infection (forestry labourers, forestry workers and huntsmen). All blood samples were analyzed in the National Reference Laboratory for Lyme borreliosis CEM (LB) in the National Institute of Public Health in Prague by the ELISA NRLB KC 90 method and in case of a positive result they were confirmed by the Western blot Lyme method. All patients completed a special questionnaire used as a standard procedure in the consultation centre for LB. In the group of blood donors 100 men were examined, mean age 33.5 years and 100 women, mean age 24.4 years. In 26 positive antibodies against Borrelia burgdorferi (Bb) were confirmed, but on invitation to medical examination only 22 attended, 11 men and 11 women (10.1%). Examination of antiborrelia antibodies by the ELISA method proved positivity of class IgM 7 times and of class IgG 9 times. By the Western blot method (WB) class IgG was confirmed three times. In the risk group 39 men were examined, mean age 40.6 years and 32 women. In 12 of them (17.9%) positivity of antiborrelia antibodies against Borrelia burgdorferi (Bb) was proved by the ELISA method as well as the WB method. If the percentage confidence interval of the control group is taken as a basis for comparison, then the value of the risk group is within this interval at a significance value of alpha = 0.01. In the conclusion the authors discuss the problem of interpretation of positive serological results and the pitfalls of their evaluation not only from the aspect of validity of laboratory findings, due to the absence of standardization of methods, but also with regards to obscure aspects of the persistence of IgM antibodies after years of lege artis antibiotic treatment.

Contact with ticks and awareness of tick-borne diseases among the Czech population--a pilot study

In the Czech Republic, the incidence of Lyme borreliosis (LB) has shown a rising trend since 1988. The goal of this study has been to find out to what extent a selected part of population is aware of ticks and of the relationship between ticks and LB. The study was based on a questionnaire survey. A total of 110 respondents were selected, including 19 secondary school students, 32 blood donors, 44 park-goers, 15 countryside people. As many as 99% of the respondents were aware of the presence of ticks, 91% knew that ticks are sucking blood of humans and animals, 1.8% thought they eat leaves. 74.5% of the respondents expect ticks to reach them from the vegetation while 22% believe that ticks fall from the trees. Furthermore, 87% and 75% of the respondents indicated to have had ticks attached to the skin or to have removed a tick from other persons' skin, respectively. Only 6.7% of them had never come into contact with ticks. 17% of the respondents use disinfectant when removing a tick, while 67% use oil for tick removal. Almost 30% remove ticks with naked hands. Over 14% destroy the ticks by squashing them with naked fingers. Finally, about 11% of the population studied had never heard about LB and 41% were not aware of the risk of tick-borne encephalitis.

[Educational status of the Czech population about Lyme borreliosis and experience with tick bites--pilot study]

The incidence of Lyme borreliosis (LB) has a rising trend since 1995. In 1995 6,302 cases were reported, in 1996 4,192 (EPIDAT, SZU). The objective of the present work was to assess in a selected population sample knowledge of ticks and their relationship to Lyme borreliosis. The investigation was based on a survey using questionnaires. 110 respondents were selected according to the following pattern: 19 secondary school students, 32 blood donors, 44 visitors of parks, 15 countryside people. 99.1% of the subjects knew about the existence of ticks in the Czech Republic, 10.9% of the respondents do not know about Lyme borreliosis. More than 80% of the people are in the countryside at least once a week. 87% of the people report they had a tick, 75% removed a tick from another person. Only 6.7% of the respondents never had any contact with ticks. When removing ticks 17% of the subjects use disinfection, 67% use oil. Almost 30% of the respondents remove ticks with bare hands and more than 14% destroy them by squashing them between their fingers. 41% are not aware of the risk of transmission of tick-borne encephalitis. From the investigation a frequent contact of the population with ticks is apparent. Theoretical knowledge of the problem is extensive, practical experience is different. Unfortunately unsuitable habits in removal of ticks persist and this increases the risk of transmission of Lyme borreliosis.

[IgG antibodies to Borrelia in dogs in the area of Kosice]

An ELISA investigation showed that 26.9% of dogs in Kosice region were positive for anti-borrelia IgG antibodies. A significantly higher seroprevalence was detected only in hunting dogs (40.0%) compared with service dogs (11.8%; p < 0.05). An analysis of seroprevalence by age showed a significant difference only between dogs in the categories 1-3 years (37.8%) and under 1 year of age (8.3%; p < 0.05). In other age groups no significant differences in seroprevalence were observed. No significant difference in seroprevalence was detected between sex either. A high correlation was determined to exist between the seroprevalence and the number of engorged ticks (R = 0.8) and the frequency of the exposure of dogs to the tick-infested wooded areas with the focal occurrence of boreliae (R = 1). The analysis of results suggests that seroprevalence of Lyme borreliosis in dogs of the Kosice region is not negligible. The breed, age and sex do not influence the seroprevalence of the disease. The decisive role is, however, played by the time of the exposure of dogs to the environment infested by Borrelia-contaminated ticks.

Electron microscopy and the polymerase chain reaction of spirochetes from the blood of patients with Lyme disease

Results of studies using direct antigen detection suggest that seronegative Lyme borreliosis is not rare and support the hypothesis that Borrelia antigens can persist in humans. We report three successful cultures from blood out of 30 attempts from 96 Lyme disease patients. The proof of borreliaemia in early or late phases of Lyme disease by immuno-capture electron microscopy has practical importance for subsequent cultivation. The polymerase chain reaction with oligonucleotide sequences directed against 16S rRNA identified two of our blood isolates as Borrelia burgdorferi genospecies III., VS 461 group, and one as Borrelia garinii sp. nov. All of the three isolates were reactive with monoclonal antibody H9724 against flagellin and with antibody against main extracellular protein at 83 kDa. Borrelia garinii had a single predominant protein OspA at 33.5 kDa and reacted with monoclonal antibody H5332 in contrast to two isolates of the VS 461 group with two major proteins OspA and OspB at 32.5 and 35 kDa. We conclude that isolation of spirochetes from the blood might prove successful in clinically selected cases of Lyme borreliosis. Immuno-capture electron microscopy has proved to be a sensitive assay for monitoring and studying Lyme borreliosis.

[Early-stage lyme borreliosis during pregnancy: treatment in 15 women with erythema migrans]

The authors treated and followed-up since July 1987 9 women with non-complicated erythema migrans and 4 women with erythema migrans associated with general signs and symptoms during pregnancy; two patients were treated only after delivery. For treatment antibiotics of the penicillin series were used. The course of gestation in 14 patients was without complications, one patient was followed-up on account of oedema of the lower extremities. The infants of 14 women were born in term, one infant was born during the 37th week of gestation. All infants were eutrophic. Umbilical blood for serological examination was collected from 8 infants, elevated IgG antibody levels against Borrelia burgdorferi were detected in one. The post-partum development of all infants was normal. During the subsequent follow-up for 6-26 months elevated antibodies against Borrelia burgdorferi were not found in any of the 4 infants subjected to serological examination. One child was operated at the age of one year on account of a patent ductus arteriosus, another child was treated at the age of two years on account of cryptorchism, two children were treated on account of hypoplastic enamel, in one infant at the age of 10 months the psychomotor development was retarded by two months. Transplacental transmission of Borrelia burgdorferi was not proved. With regard to the variety of the observed deviations and the small number of data the problem of a possible teratogenic action of this spirochete remains open.

[Experience with Neisseria lactamica (author's transl)]

The authors have performed a detailed study of the presence of a new microbial species, Neisseria lactamica which even recently had still been classified among the nontypable Neisseria meningitidis strains. An examination of the spread of Neisseria strains among the healthy population of this country revealed 1.6% to be carriers of Neisseria lactamica as compared with 4.7% being carriers of Neisseria meningitidis. From the material examined, the highest number of Neisseria lactamica carriers was found among the 0-1 year age group (5.9%) whereas the maximum number of Neisseria meningitidis carriers was found in the 25-34 year age group (11.1%). The simultaneous identification of N. meningitidis and N. lactamica in exceptional cases means a new and important observation.

[Action of chemotherapeutics upon Neisseria meningitidis (author's transl)]

During the period 1970-1973 (1st half), 281 strains of Neisseria meningitidis from carriers and 35 from patients were tested for their sensitivity to a wide spectrum of chemotherapeutics. From the results of the tests for sensitivity in vitro, the conclusion is drawn that ampicillin, carbenicillin, and rifamycin SV may be considered as having a good action upon Neisseria meningitidis. The preparations of intermediate efficacy include penicillin, cephaloridine, chloramphenicol, and tetracyclin. As to sulphonamides, the presence of resistant strains was established. This phenomenon was rare when sulphonamide had been combined with trimetoprim.

[Effect of tylosin in pigs]

The effect of tylosine and sulphadimidine, chlortetracycline, and bacitracin in feed was studied in 1275 piglets from 120 litters; the values obtained were compared with the control group given no antibiotics. Three Tylan injections were applied to a half of the animals on the 2nd, 5th, and 28th day after birth. The Tylan program did not lead to any significant reduction of piglet mortality before the 50th day of life. In neither of the groups did Tylan injections reduce mortality at the level of statistical significance. From the age of 56 days, the Tylan-application program provides statistically significant weight gains, as compared with other groups. The group with Czechoslovak antibiotics had the same weight as the group fed without antibiotics. The occurrence of pathological and anatomic findings on lungs showed no statistically significant differences in the two groups. The presence of tylosine in blood could not be ascertained after the oral application of even much higher doses than those used in the Tylan-application program. Small incidence of rhinitis does not allow for drawing any conclusions concerning the effects of Tylan.