An Age-stratified, Randomized Immunogenicity Trial of Killed Oral Cholera Vaccine with Delayed Second Dose in Cameroon

The recommended schedule for killed oral cholera vaccine (OCV) is two doses, 2 weeks apart. However, during vaccine campaigns, the second round is often delayed by several months. Because more information is needed to document antibody responses when the second dose is delayed, we conducted an open-label, phase 2, noninferiority clinical trial of OCV. One hundred eighty-six participants were randomized into three dose-interval groups (DIGs) to receive the second dose 2 weeks, 6 months, or 11.5 months after the first dose. The DIGs were stratified into three age strata: 1 to 4, 5 to 14, and > 14 years. Inaba and Ogawa vibriocidal titers were assessed before and after vaccination. The primary analysis was geometric mean titer (GMT) 2 weeks after the second dose. Data for primary analysis was available from 147 participants (54, 44, and 49 participants from the three DIGs respectively). Relative to the 2-week interval, groups receiving a delayed second dose had significantly higher GMTs after the second dose. Two weeks after the second dose, Inaba GMTs were 55.1 190.3, and 289.8 and Ogawa GMTs were 70.4, 134.5, and 302.4 for the three DIGs respectively. The elevated titers were brief, returning to lower levels within 3 months. We conclude that when the second dose of killed oral cholera vaccine was given after 6 or 11.5 months, vibriocidal titers were higher than when given after the standard period of 2 weeks. This provides reassurance that a delayed second dose does not compromise, but rather enhances, the serological response to the vaccine.

Drug Safety Monitoring in Health Programs of Cameroon

BACKGROUND

Data are needed to serve as evidence in planning the strengthening of pharmacovigilance in health programs administering drugs to populations. The present study was proposed to map the distribution of pharmacovigilance units in health programs, assess the availability of key resources, the implementation of key pharmacovigilance activities and identify needs of involved actors.

METHODS

It was a cross sectional descriptive study targeting all health programs of the Cameroon Ministry of Public Health administering drugs/vaccines to the population. Data were collected using semi structured questionnaire administered face to face to key persons in charge of drug safety monitoring or drug management in health programs.

RESULTS

Out of the 09 health programs involved in drug distribution, 07 consented to participate. Five out of them (71.4%) claimed to have existing pharmacovigilance units. Office space, computers, operating budget, data analysis software and a trained staff were available in 28.6%, 42.9%, 42.9%, 14.3%, 00.0%, and 42.9% of the health programs respectively. One of the 7 health programs (14.3%) declared conducting detection/notification of adverse events following exposure drugs, 2 (28.6%) conduct causality assessment and 3 (42.8%) conduct analysis of pharmacovigilance data. All health programs proposed to prioritize the allocation of budget and qualified personnel and the training of existing personnel as key interventions to improve drugs/vaccines safety monitoring in health programs.

CONCLUSION

The study reports limited coverage of Cameroon health programs with activities leading to drugs and vaccine safety monitoring. Suggested actions have to be taken into account when attempting to improve the situation.

Training needs of health researchers in research ethics in Cameroon: a cross-sectional study

BACKGROUND

Researchers are responsible for the protection of health research participants. The purpose of this study was to identify and prioritize the training needs of researchers involved in human health research in Cameroon.

METHODS

It was a cross-sectional study conducted in all the Cameroon regions in the last quarter of 2020. It targeted researchers involved in human health research selected by systematic stratified sampling from health and training institutions, and health facilities. Data were collected using a face-to-face administered questionnaire deployed in Smartphones via the ODK-collect. The distribution of participants' exposure to research ethics training was described as well as their knowledge on the related regulatory texts. A score was used to rank the training needs identified by the participants.

RESULTS

Of 168 reached participants, 134 (79.76%) participated in the study. A total of 103 (76.87%) researchers reported having received training in human health research ethics and 98 (73.13%) perceived need of training in research ethics. Of those involved in clinical, vaccine, and field trials, 63.64, 33.33, 52.53% have been exposed respectively to related training regarding participants' protection. Having received at least one training in research ethics significantly increase the proportion of researchers systematically submitting application for ethical evaluation prior to implementation (OR = 3.20 (1.31-7.78)). Training priorities identified by researchers include: guidelines and regulations on health research ethics and research participant's protection in Cameroon, procedures for evaluating research protocols, protection of research participants in clinical trials, and fundamental ethics principles.

CONCLUSION

The coverage of researchers in training regarding research participant protection remains limited in a number of areas including those related to clinical trial participant protection and research participant protection in Cameroon. Improving this coverage and addressing perceived needs of researchers are expected to contribute in improving their ability in playing their role in research participant protection.

Tracking Demographic Movements and Immunization Status to Improve Children's Access to Immunization: Field-Based Randomized Controlled Trial

Background

Countries’ Expanded Program on Immunization (EPI) contribute to the reduction of mortality and morbidity, but access to these vaccines remains limited in most low-income countries.

Objective

We aim to assess whether involving community volunteers (CVs) to track children’s vaccination status and demographic movements and using recorded data to plan catch-up immunization sessions can improve children’s vaccination timeliness, completeness, and coverage.

Methods

This was a field-based randomized controlled trial and communities of the Foumban health district in West Cameroon were allocated to intervention or control groups. In the intervention group, a CV per community was trained to visit households monthly for a year to assess and record in a register, details of EPI-targeted children, their demographic movements and immunization status. The scanned recorded pages were sent to the health center immunization team through WhatsApp and used to organize monthly community catch-up immunization sessions. In the control group, EPI vaccination sessions were routinely conducted. Surveys were conducted at 6 and 12 months from the beginning of the intervention in both study groups to assess and compare immunization timeliness, coverage, and completeness.

Results

Overall, 30 buildings per cluster were surveyed at midline and endline. Of the 633 and 729 visited households in the intervention group at midline and endline, 630 (99.5%) and 718 (98.4%), respectively, consented to participate. In the control group, 507 and 651 households were visited and 505 (99.6%) and 636 (97.7%), respectively, consented to participate. At 12 months intervention, the month one timeliness of bacille Calmette–Guerin (BCG) vaccine did not increase in the intervention group compared with the control group for the age groups 0-11 months (adjusted odds ratio [aOR] 1.1, 95% CI 0.7-1.8) and 0-59 months (aOR 1.1, 95% CI 0.9-1.4), and significantly increased for the first-year BCG vaccine administration for the age group 0-23 months (aOR 1.5, 95% CI 1.1-2.2). The coverage of diphtheria-pertussis-tetanus and hepatitis B+Hemophilus influenzae type B (DPT-Hi +Hb) dose 3 (aOR 2.0, 95% CI 1.5-2.7) and of DPT-Hi+Hb dose 1 (aOR 1.8, 95% CI 1.4-2.4) vaccines increased significantly in the intervention group compared with the control group in the age groups 12-59 months and 12-23 months, respectively. Specific (DPT-Hi+Hb dose 1 to DPT-Hi+Hb dose 3: aOR 1.9, 95% CI 1.4-2.6) and general (BCG to measles: aOR 1.5, 95% CI 1.1-2.1) vaccine completeness increased significantly in the intervention group compared with the control group.

Conclusions

Findings support that involving CVs to track children’s vaccination status and demographic movements and using recorded data to plan catch-up immunization sessions improve children’s vaccination timeliness, completeness, and coverage. This strategy should be adopted to improve access to vaccination for EPI target populations and the consistency verified in other contexts.

Trial Registration

Pan African Clinical Trials Registry PACTR201808527428720; https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=3548