The protective effect of COVID-19 vaccines on developing multisystem inflammatory syndrome in children (MIS-C): a systematic literature review and meta-analysis

Child COVID-19 vaccine uptake among participants of the 2015 Pelotas (Brazil) Birth Cohort Study

OBJECTIVE

To analyze COVID-19 vaccine uptake in children and to investigate factors associated with two outcomes variables: (a) not even beginning; (b) not completing the COVID-19 vaccine series.

METHODS

We used data of children aged 6-7 years from the 2015 Pelotas c Birth Cohort Study. COVID-19 vaccination status was collected from immunization cards and National Immunization Program Information System. Adjusted analyses were performed using a hierarchical model to identify factors associated with the two study outcomes.

RESULTS

Among 3867 children, 20.7 % (95 % CI, 19.5 %-22.0 %) did not even begin the 2-dose primary COVID-19 vaccine series, and 28.2 % (95 % CI, 26.6 %-29.8 %) did not complete the series with the second dose. Children not even beginning the COVID-19 vaccine series were more likely to have a White mother, not to have obesity, to have a history of COVID-19 infection, to have received non-recommended drugs for COVID-19, to be afraid of needles, and to have an incomplete diphtheria-tetanus-pertussis (DTP) and poliovirus immunization schedule. Not completing the 2-dose series was associated with lower maternal age and education, mother's self-identification as White or Brown, lower household income, lack of access to health services, not having completed the DTP and poliovirus immunization schedule and living with a person with a history of infection with COVID-19.

CONCLUSION

The results highlight a vaccine-hesitant parents' group who chose not beginning the COVID-19 vaccine series of their children and, another group of parents who failure to complete the child's series due to difficulty accessing health services.

Dynamics of multisystem inflammatory syndrome in children associated to COVID-19 in Chile: Epidemiologic trends during pandemic, before and after children vaccination

BACKGROUND

Multisystem inflammatory syndrome associated to Covid-19 (MIS-C) is one of the most severe outcomes of SARS-CoV-2 in children. Covid-19 vaccines were successfully implemented in Chile for the pediatric population since 2021, using both mRNA and inactivated platforms. Effectiveness against MIS-C has been reported for mRNA vaccines. The aim of this study was to describe the epidemiologic trend of MIS-C in Chile during Covid-19 pandemic, both before and after the availability of vaccination for children.

MATERIALS AND METHODS

Analytic study of MIS-C cases from April 2020 to December 2022. Epidemiological data, SARS-CoV-2 variants and vaccination uptake information were obtained from the Epidemiology Department-Ministry of Health, Institute of Public Health and the National Immunization Program, respectively.

RESULTS

496 cases of MIS-C were reported, 58 % males. Median age was 5 years and most frequent age-cohorts were 6-11 and 0-2 years old with a 33 % each. After the introduction of the Covid-19 vaccine, most cases occurred in children aged 0-2 years. Incidence rates were 3.8, 5.4 and 1.7 per 100,000 inhabitants in 2020, 2021 and 2022, respectively. 97 % of cases (481) occurred in unvaccinated subjects. On those previously vaccinated (15), all but one case occurred in children receiving the inactivated vaccine. No association among circulating variants and incidence was observed. Incidence rate reduction (IRR) comparison between 2020 and 2021-2022 periods was 0.72 (CI 95 % 0.65-0.81, p < 0.05) overall; 0.86 for 0-2 years (CI 95 %:0.71-1; p = 0.12); 0.88 for 3-5 years (CI 95 %:0.69-1.11; p = 0.28); 0.61 for 6-11 years (CI 95 %: 0.50-0.75; p < 0.05); and 0.64 for 12-17 years (CI 95 %:0.47-0.89; p < 0.05), consistent with vaccination uptake during the studied period: 63 % for 3-5 years, 91 % for 6-11 years, and 99 % for 12-17 years.

CONCLUSIONS

A decline of MIS-C incidence and a shift to younger, unvaccinated population overtime was observed. IRR decreased in age-cohorts which achieved high vaccination rates.

What the SARS-CoV-2 Pandemic Has Taught Us About Immunosuppression, Vaccinations, and Immune Dysregulation: The Rheumatology Experience

PURPOSE OF REVIEW

This review reflects on the impact of the COVID-19 pandemic on the field of rheumatology, emphasizing resulting insights related to the risks of viral infections in immunosuppressed patients, vaccine immunogenicity in immunocompromised patients, and immune dysregulation in the setting of viral infection.

RECENT FINDINGS

During the pandemic, global patient registries provided real-time insights into the risk factors associated with severe COVID-19 outcomes in rheumatology patients. Updated evidence-based recommendations from the American College of Rheumatology (ACR) guided rheumatology practice during a time of considerable uncertainty. Studies on COVID-19 vaccines in immunocompromised populations enhanced our understanding of specific immunosuppressive therapies on vaccine efficacy. The immune dysregulation seen in severe COVID-19 underscored a role for immunomodulation in this and other severe infections. Furthermore, novel post-infectious conditions, namely multisystem inflammatory syndrome in children (MIS-C) and Long COVID, reshaped our understanding of post-viral syndromes and revealed novel pathological mechanisms. Lessons from the COVID-19 pandemic demonstrate the power of collaborative research. The scientific revelations from this dreadful time will, nonetheless, benefit the practice of rheumatology for years to come.

Differences in the Clinical Manifestations and Host Immune Responses to SARS-CoV-2 Variants in Children Compared to Adults

The COVID-19 pandemic challenged the medical field to rapidly identify and implement new approaches to the diagnosis, treatment and prevention of SARS-CoV-2 infections. The scientific community also needed to rapidly initiate basic, translational, clinical and epidemiological studies to understand the pathophysiology of this new family of viruses, which continues to evolve with the emergence of new genetic variants. One of the earliest clinical observations that provided a framework for the research was the finding that, in contrast to most other respiratory viruses, children developed less severe acute and post-acute disease compared to adults. Although the clinical manifestations of SARS-CoV-2 infection changed with each new wave of the pandemic, which was dominated by evolving viral variants, the differences in severity between children and adults persisted. Comparative immunologic studies have shown that children mount a more vigorous local innate response characterized by the activation of interferon pathways and recruitment of innate cells to the mucosa, which may mitigate against the hyperinflammatory adaptive response and systemic cytokine release that likely contributed to more severe outcomes including acute respiratory distress syndrome in adults. In this review, the clinical manifestations and immunologic responses in children during the different waves of COVID-19 are discussed.

COVID-19 Vaccine for Children: Determinants and Beliefs Contributing to Vaccination Decision of Parents in Germany 2021/2022

To reduce the number of COVID-19 cases, vaccines were rapidly made available worldwide. For a strategically targeted response to the COVID-19 pandemic, population vaccination coverage was to be maximized. The target groups also included healthy children. In this context, it is important to understand the determinants and beliefs that lead parents to favor or oppose COVID-19 immunization in children. This study aimed to investigate parents' COVID-19 vaccination willingness in Germany for children aged 5-11 years in 2021/2022. For this purpose, the determinants and beliefs behind parents' vaccination decisions were examined. Descriptive analysis and bivariate correlations were performed on COVID-19 vaccination willingness and parents' mental health status, general vaccination attitudes, and SARS-CoV-2 politics perceptions. In total, 2401 participants fully participated in this cross-sectional study. The COVID-19 vaccination uptake (71.4%) outweighed the vaccination refusal (19.4%). Correlations revealed higher vaccine acceptance in parents presenting full vaccination certificates (90.9%), COVID-19 immunizations (99.9%), or increased COVID-19 fear (93.6%). Vaccination-refusal was associated with higher perceived pressure by COVID-19 vaccination campaigns (87.7%), higher experienced restrictions due to COVID-19 protective measures in parents' social environment (83.6%), and engagement against COVID-19 protective measures (51.6%). Besides general anxiety, no significant correlations were observed between parents' mental health variables and vaccination willingness. Although several factors are ultimately associated with vaccination willingness, future vaccination campaigns should prioritize reducing pressure, increasing trust, and considering parents' differentiation between familiar and unfamiliar pathogens during their vaccination decision-making process.