Vaccinology in sub-Saharan Africa

Expanding the reach of vaccinology training in Africa: leveraging the success of the Annual African Vaccinology Course

Introduction

It is estimated that one in five African children lack access to recommended life-saving vaccines. This situation has been exacerbated by the COVID-19 pandemic which disrupted routine immunization services in several parts of the region. To better support recovery efforts and get immunization programmes back on track, policy makers, programme managers, immunization providers and academics need continuous upskilling. Unfortunately, the vaccinology training needed by these cadres remains limited and oftentimes inaccessible within our context. In addition, cadres should be continuously updated on advances in vaccinology so as to keep abreast with this rapidly evolving field. This calls for new and accessible approaches to training vaccinologists in Africa where the demand is high.

Methods

The aim of this proof-of-concept study was to ascertain the training needs of alumni of the Annual African Vaccinology Course and assess the effectiveness of an online webinar series in meeting those needs.

Results

We found that alumni from across Africa required refresher training to gain up-to-date information about new developments in vaccinology, leverage opportunities to reinforce and consolidate their knowledge, and exchange country-specific experiences with their counterparts. A prominent motivation for refresher training was the rapid developments and challenges brought on by the COVID-19 pandemic. Drawing on the expressed needs of our alumni, we developed a webinar training series. This series aimed to provide participants with training on current and emerging trends in vaccinology with a focus on the regional context. Online participation in the webinar series was found to be comparable to previous in-person training, reaching a diverse group of cadres, and allowing for participation of a richer global faculty due to fewer cost constraints. Further to this, a post-training survey indicated that generally, alumni training needs were successfully met.

Discussion

The findings suggest that an online approach can be used to expand the reach of vaccinology training in Africa.

Advanced vaccinology training globally: Update and impact of the COVID-19 crisis

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A total of 33 advanced vaccinology courses were in existence in 2021.

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Some vaccinology courses were not sustained since 2018.

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The number of vaccinology courses has been increasing during the last few years, with courses offered in each WHO region.

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The COVID-19 pandemic resulted in the cancellation or postponement of some vaccinology courses.

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Due to the COVID-19 pandemic, an increased number of courses are using an online or hybrid format.

The rapid development of innovations and new technologies, the focus on the life-course approach to immunization and equity, and the prevalent hesitancy towards vaccines requires immunization staff to be well-trained and updated regularly in order to deliver quality immunization services to the public. The need for advanced vaccinology training is therefore paramount. In preparation for a second Global Workshop on Advanced Vaccinology Training that took place in March 2022, this paper presents the results of a survey aiming to provide a thorough update of a landscape analysis on advanced vaccinology courses conducted in 2018 and a look at the impact of the COVID-19 crisis. Thirty-three course organizers responded to a survey to provide information on their respective course. Of those, 17 courses are short courses, 11 post-graduate courses and 5 are Master level courses. Most courses are organized on an annual basis. Even though some courses were not sustained overtime, the number of courses has been increasing during the last few years, and at least one vaccinology course is now being offered in each WHO region. Although the training capacity has increased tremendously, the need still exceeds the capacity and many courses have way more applicants than they can select. The most frequent challenges reported included sustainable funding and identifying faculty. The COVID-19 pandemic impacted the delivery of several vaccinology courses, which have been postponed or reformatted to an online or hybrid training event. An e-portal of the global collaboration has been established to facilitate communication between the different courses and to assist future course participants to identify the most suitable course for their needs.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Africa: Current Considerations and Future Projections

The burden of severe Covid-19 has been relatively low in sib-Saharan Africa compared to Europe and the Americas. However, SARS-CoV-2 sero-prevalence data has demonstrated that there has been more widespread transmission than can be deduced from reported cases. This could be attributed to under reporting due to low testing capacity or high numbers of asymptomatic SARS-CoV-2 infection in communities. Recent data indicates that prior SARS-CoV-2 exposure is protective against reinfection and that vaccination of previously SARS-CoV-2 infected individuals induces robust cross-reactive antibody responses. Considering these data, calls for a need for a re-think of the COVID-19 vaccination strategy in sub-Saharan African settings with high SARSCoV-2 population exposure but limited available vaccine doses. A potential recommendation would be to prioritize rapid and widespread vaccination of the first dose, while waiting for more vaccines to become available.

Mental Health during the COVID-19 Crisis in Africa: A Systematic Review and Meta-Analysis

We aim to provide a systematic review and meta-analysis of the prevalence rates of mental health symptoms among major African populations during the COVID-19 pandemic. We include articles from PubMed, Embase, Web of Science, PsycINFO, and medRxiv between 1 February 2020 and 6 February 2021, and pooled data using random-effects meta-analyses. We identify 28 studies and 32 independent samples from 12 African countries with a total of 15,071 participants. The pooled prevalence of anxiety was 37% in 27 studies, of depression was 45% in 24 studies, and of insomnia was 28% in 9 studies. The pooled prevalence rates of anxiety, depression, and insomnia in North Africa (44%, 55%, and 31%, respectively) are higher than those in Sub-Saharan Africa (31%, 30%, and 24%, respectively). We find (a) a scarcity of studies in several African countries with a high number of COVID-19 cases; (b) high heterogeneity among the studies; (c) the extent and pattern of prevalence of mental health symptoms in Africa is high and differs from elsewhere-more African adults suffer from depression rather than anxiety and insomnia during COVID 19 compared to adult populations in other countries/regions. Hence, our findings carry crucial implications and impact future research to enable evidence-based medicine in Africa.

Mental Health during the COVID-19 Crisis in Africa: A Systematic Review and Meta-Analysis

We aim to provide a systematic review and meta-analysis of the prevalence rates of mental health symptoms among major African populations during the COVID-19 pandemic. We include articles from PubMed, Embase, Web of Science, PsycINFO, and medRxiv between 1 February 2020 and 6 February 2021, and pooled data using random-effects meta-analyses. We identify 28 studies and 32 independent samples from 12 African countries with a total of 15,071 participants. The pooled prevalence of anxiety was 37% in 27 studies, of depression was 45% in 24 studies, and of insomnia was 28% in 9 studies. The pooled prevalence rates of anxiety, depression, and insomnia in North Africa (44%, 55%, and 31%, respectively) are higher than those in Sub-Saharan Africa (31%, 30%, and 24%, respectively). We find (a) a scarcity of studies in several African countries with a high number of COVID-19 cases; (b) high heterogeneity among the studies; (c) the extent and pattern of prevalence of mental health symptoms in Africa is high and differs from elsewhere-more African adults suffer from depression rather than anxiety and insomnia during COVID 19 compared to adult populations in other countries/regions. Hence, our findings carry crucial implications and impact future research to enable evidence-based medicine in Africa.

Review of preventative HIV vaccine clinical trials in South Africa

New HIV infections continue relentlessly in southern Africa, demonstrating the need for a vaccine to prevent HIV subtype C. In South Africa, the country with the highest number of new infections annually, HIV vaccine research has been ongoing since 2003 with collaborative public-private-philanthropic partnerships. So far, 21 clinical trials have been conducted in South Africa, investigating seven viral vectors, three DNA plasmids, four envelope proteins, five adjuvants and three monoclonal antibodies. Active vaccine candidates have spanned subtypes A, B, C, E and multi-subtype mosaic sequences. All were well tolerated. Four concepts were investigated for efficacy: rAd5-gag/pol/nef showed increased HIV acquisition in males, subtype C ALVAC/gp120/MF59 showed no preventative efficacy, and the trials for the VRC01 monoclonal antibody and Ad26.Mos4.HIV/subtype C gp140/ aluminum phosphate are ongoing. Future trials are planned with DNA/viral vector plus protein combinations in concert with pre-exposure prophylaxis, and sequential immunization studies with transmitted/founder HIV envelope to induce broadly neutralizing antibodies. Finally, passive immunization trials are underway to build on the experience with VRC01, including single and combination antibody trials with an antibody derived from a subtype-C-infected South African donor. Future consideration should be given to the evaluation of novel strategies, for example, inactivated-whole-virus vaccines.

HIV Env-Specific IgG Antibodies Induced by Vaccination of Neonatal Rhesus Macaques Persist and Can Be Augmented by a Late Booster Immunization in Infancy

The HIV epidemics in infants and adolescent women are linked. Young women of childbearing age are at high risk for HIV infection and, due to poor HIV testing rates and low adherence to antiretroviral therapy, are at high risk for mother-to-infant transmission. We hypothesize that HIV vaccine regimens initiated in early life would provide the necessary time frame to induce mature and highly functional Env-specific antibody responses that could potentially also protect against HIV acquisition later in life. The present study was designed to test two vaccine regimens, a clade C HIV Env protein vaccine (Env only) alone or combined with a modified vaccinia Ankara (MVA) vector expressing HIV Env (MVA/Env) for the induction and persistence of Env-specific antibody responses in an infant nonhuman primate model. Vaccination was initiated within the first week of life, with booster immunizations at weeks 6, 12, and 32. We demonstrate that both vaccine strategies were able to elicit durable Env-specific antibody responses that were enhanced by a late boost in infancy. Furthermore, we confirmed earlier data that intramuscular administration of the Env protein with the Toll-like receptor 7/8 (TLR7/8)-based adjuvant 3M-052 in stable emulsion (3M-052-SE) induced higher Env-specific antibody responses than vaccination with Env adjuvanted in Span85-Tween 80-squalene (STS) tested in a previous study. These results support the concept of early vaccination as a means to induce durable immune responses that may prevent HIV infection in adolescence at the onset of sexual debut.IMPORTANCE The majority of new HIV-1 infections occur in young adults, with adolescent women being 3 times more likely to acquire HIV than young men. Implementation of HIV prevention strategies has been less successful in this age group; thus, a vaccine given prior to adolescence remains a high priority. We propose that instead of starting HIV vaccination during adolescence, an HIV vaccine regimen initiated in early infancy, aligned with the well-accepted pediatric vaccine schedule and followed with booster immunizations, will provide an alternative means to reduce HIV acquisition in adolescence. Importantly, the long window of time between the first infant vaccine dose and the adolescence vaccine dose will allow for the maturation of highly functional HIV Env-specific antibody responses. Our study provides evidence that early life vaccination induces durable Env-specific plasma IgG responses that can be boosted to further improve the quality of the antibody response.