A review of the safety of vaccines used in routine immunization in Africa

Pharmacovigilance for Vaccines Used in Pregnancy: A Gap Analysis From Uganda

BACKGROUND

Despite the effectiveness of maternal vaccines, low- and middle-income countries grapple with inadequate safety monitoring systems. Robust safety surveillance is crucial to increasing vaccine confidence and timely identifying any potential safety signal that could put pregnant women and children at risk following vaccination. This study assessed the pharmacovigilance (PV) systems for vaccines used in pregnancy in Uganda.

METHODS

A qualitative study involves 13 key informant interviews and 8 focus group discussions among key stakeholders. Purposive sampling was used to select study participants. Data analysis was done using Miles and Huberman's matrices approach and conducted in Atlas.ti software.

FINDINGS

A passive system involving multistakeholders at various levels of the healthcare structure existed but was inadequate for monitoring adverse events following maternal immunization. The existence of parallel reporting systems for vaccines was noted. Heavy workload, lack of feedback, inadequate knowledge to recognize and report adverse events following maternal immunizations and logistical challenges impeding reporting and follow-up were among the barriers to reporting. Electronic medical records, though underutilized for safety surveillance, offer promising potential.

CONCLUSIONS

To address the specific needs of maternal vaccination, the PV system in Uganda needs improvement. A multipronged approach, including policy coherence, embracing active surveillance and leveraging existing birth outcome surveillance and electronic medical records, is essential. Harnessing healthcare provider knowledge and advisory committee capacity in causality assessment is also necessary. The study findings can inform priority interventions to enhance PV for existing and new maternal vaccines.

Observational analysis of the immunogenicity and safety of various types of spinal muscular atrophy vaccines

BACKGROUND

This study aimed to evaluate the immunogenicity and safety of different types of poliovirus vaccines.

METHODS

A randomized, blinded, single-center, parallel-controlled design was employed, and 360 infants aged ≥ 2 months were selected as study subjects. They were randomly assigned to bOPV group (oral Sabin vaccine) and sIPV group (Sabin strain inactivated polio vaccine), with 180 infants in each group. Adverse reaction events in the vaccinated subjects were recorded. The micro-neutralization test using cell culture was conducted to determine the geometric mean titer (GMT) of neutralizing antibodies against poliovirus types I, II, and III in different groups, and the seroconversion rates were calculated.

RESULTS

Both groups exhibited a 100% seropositivity rate after booster immunization. The titers of neutralizing antibodies for the three types were predominantly distributed within the range of 1:128 to 1:512. The fold increase of type I antibodies differed markedly between the two groups (P < 0.05). Moreover, the fold increase of type II and type III antibodies for poliovirus differed slightly between the two groups (P > 0.05). The fourfold increase rate in sIPV group was drastically superior to that in bOPV group (P < 0.05). When comparing the post-immunization GMT levels of type I antibodies in individuals who completed the full course of spinal muscular atrophy vaccination, bOPV group showed greatly inferior levels to sIPV group (P < 0.05). For type II and type III antibodies, individuals in bOPV group demonstrated drastically superior post-immunization GMT levels to those in sIPV group (P < 0.05). The incidence of adverse reactions between the bOPV and sIPV groups differed slightly (P > 0.05).

CONCLUSION

These findings indicated that both the oral vaccine and inactivated vaccine had good safety and immunogenicity in infants aged ≥ 2 months. The sIPV group generated higher levels of neutralizing antibodies in serum, particularly evident in the post-immunization GMT levels for types II and III.

Assessment of adherence to pre-vaccination precautions and AEFI reporting practices during BCG vaccination in 4 hospitals in Ghana

The BCG vaccine, like all other vaccines, is associated with adverse events following immunization (AEFI). Reducing the incidence of AEFI is crucial in reposing confidence in BCG vaccination and reducing hesitancy associated with the vaccine. This requires safety precautions before and during vaccinations, as well as reporting AEFIs after vaccination. This study assessed the adherence of health-care professionals to pre-vaccination precautions and adverse events following immunization (AEFI) reporting practices during BCG vaccination in four hospitals in Ghana. It is hoped that the findings of the study will serve as a baseline to identify gaps for further studies to generate a stronger evidence for policy formulation aimed at improving BCG vaccine safety in Ghana and other tuberculosis endemic countries. A cross-sectional study design was employed, and Statistical Package for Social Sciences, IBM® SPSS version 25 (SPSS Inc. USA) software was used for analysis. Chi-square and binary logistic regression tests were used to test the association between categorical variables and predictors of adherence to pre-BCG vaccination precautions, respectively, and a p-value of <.05 was considered statistically significant. The AEFIs commonly reported by mothers included abscess, injection site pain, injection site redness, fever, rash, muscle weakness, diarrhea, vomiting, coughing and rhinitis. Ninety-three participants (73.2%) were adherent to pre-BCG vaccination precautions. Ninety-two participants (72.4%) informed mothers to report all AEFIs encountered. Adherence to pre-BCG vaccination precautions and AEFI reporting were generally good; however, there is still room for improvement.

Safety of Vaccination within First Year of Life-The Experience of One General Medicine Center

Vaccines represent an important preventive strategy in paediatric populations, but the rate of vaccination has been constantly declining in the last decade. Concerns about vaccines' safety represent one of the main causes of vaccine hesitancy among parents. The aim of this study was the analysis of the immediate adverse reactions induced by vaccines included in the national program of immunization for the first year of life. Method: Eighty-one children born between 1st of January 2018 and 31st of March 2019 were included. The vaccination refusal rate, and incidence and severity of adverse effects induced by three mandatory vaccines (Hexavalent, Prevenar 13 and MMR) were analyzed. The level of parents' education and the sources of information that were consulted in order to understand the adverse effects were also analyzed. Results and conclusions: The rate of adverse events was lower than 30% of the total number of doses, and most of them were mild. The incidence and severity of vaccine-induced adverse effects were correlated with prematurity. The vaccine hesitancy rate was lower than the national one, possibly due to a high level of education and good information provided by doctors that might have led to parents' concerns regarding vaccination being answered.

COVID-19 pandemic: SARS-CoV-2 specific vaccines and challenges, protection via BCG trained immunity, and clinical trials

Introduction: The coronavirus disease 2019 (COVID-19) pandemic continues to spread worldwide and vaccination remains the most effective approach to control COVID-19. Currently, at least ten COVID-19 vaccines have been authorized under emergency authorization. However, these vaccines still face many challenges.Areas covered: This study reviews the concept and mechanisms of trained immunity induced by the Bacille Calmette Guérin (BCG) vaccine and identifies questions that should be answered before the BCG vaccine could be used to combat COVID-19 pandemic. Moreover, we present for the first time the details of current BCG vaccine clinical trials, which are underway in various countries, to assess its effectiveness in combating the COVID-19 pandemic. Finally, we discuss the challenges of COVID-19 vaccines and opportunities for the BCG vaccine. The literature was found by searching the PubMed (https://pubmed.ncbi.nlm.nih.gov/), Web of Science (www.webofknowledge.com), Embase (https://www.embase.com), and CNKI (https://www.cnki.net/) databases. The date was set as the default parameter for each database.Expert opinion: The advantages of the BCG vaccine can compensate for the shortcomings of other COVID-19 vaccines. If the efficacy of the BCG vaccine against COVID-19 is confirmed by these clinical trials, the BCG vaccine may be essential to resolve the challenges faced by COVID-19 vaccines.

Reproductive health issues, infections and non-communicable diseases

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