Reconsidering rebound malaria: Zanzibari voices on acquired immunity, risk, and history

The voices of Africans living in endemic malaria zones are rarely present in malaria decision making. This article lays out 4 distinct periods in Zanzibar's malaria history, present evidence of the island's past rebound epidemic in the 1970s-1980s and show that despite nearly a century of biomedical contact around malaria, there has not been prior information sharing/education about acquired immunity or the risks of rebound malaria.

The paper draws on 98 interviews with residents on the island of Zanzibar-the site of intensive international malaria interventions since the 1950s. Interviews consisted of a series of questions focused on the concepts of acquired immunity and rebound malaria while researching the larger history of malaria on the island.

Members of the lay public have little to no familiarity with the concepts of "acquired immunity" or "rebound malaria" despite 70 years of international malaria work. There is no evidence-oral or archival-that researchers have ever explained these concepts or related risks to Zanzibaris. Members of the lay public who were shown a basic visual tool about acquired immunity followed by a brief five-to-ten-minute conversation showed a changed understanding of the concepts of acquired immunity and rebound malaria, and indicated the information had value to them. High-level malaria experts are familiar with "acquired immunity" and know about Zanzibar's rebound epidemic of the 1970s-1980s. Many experts felt it was a professional duty to better inform the lay public, and that the public had a "right" (haki) to this malaria knowledge.

Zanzibaris' lack of familiarity with the concepts of acquired immunity and rebound malaria raises several serious questions. Ethical malaria interventions must honestly and clearly share relevant information. Failure to disclose risks such as fading/lost acquired immunity and rebound epidemics does not respect persons or autonomy. These findings indicate the need to shift to more robust consent practices, greater disclosure of potential risks, and more public education about these concepts. Informing Zanzibaris about the benefits and risks of malaria interventions empowers communities to participate in global health activities and recognizes the autonomy of individuals and communities.