Adverse Events Following Immunization with Novel Oral Polio Vaccine Type 2, and the Experience and Challenges of Reporting in Sierra Leone [Response to Letter]

Dear editor

Thank you for your valuable feedback and you interest in our research titled “Adverse Events Following Immunization With Novel Oral Polio Vaccine Type 2, and the Experience and Challenges of Reporting in Sierra Leone”.¹

We are pleased that you found the description of the cVDPV2 outbreak and the mixed-method approach to vaccine implementation comprehensive. Indeed, the study tried to provide a detailed understanding of how the outbreak unfolded and the subsequent vaccination efforts in Sierra Leone. The challenges faced by the vaccine implementers, particularly in overcoming logistical and social barriers, were critical to the findings.

You have raised an important point about the need for more in-depth analysis from a medical perspective regarding AEFI. We recognize the significance of providing a more robust exploration of adverse events. In response to your suggestion, we will look to expand the medical context in future follow-up studies, offering hypotheses on the nature of AEFI while maintaining a focus on data and field findings. It may include a more detailed examination of potential AEFI cases, their clinical presentations, and any patterns that emerged during the study whilst engaging with healthcare professionals to generate medically grounded hypotheses that can contribute to a more precise understanding of these events.

You also suggested to include focus group discussions with vaccinators and this is very well noted. Such an approach could provide invaluable insights into the perceptions and experiences of those directly involved in the vaccination process.

Perhaps in future studies, we will consider incorporating this qualitative method to better capture the nuanced challenges faced by vaccinators, as well as their direct interactions with the public as this will help in creating a more comprehensive picture of client perspectives and attitudes toward vaccination.

We also agree that offering narratives on AEFI is essential in addressing public concerns about vaccine safety. One of the aims of our research was to clarify the lack of a causal relationship between vaccination and adverse events.

However, your feedback emphasizes the need to more explicitly communicate these findings to reinforce public confidence in vaccination programs. As a result, we will ensure that future work includes a more detailed narrative that highlights this.

We look forward to incorporating these suggestions into future research endeavors and improving the clarity and scope of our work.