Clinical and public health evidence suggest that the MDA of azithromycin to eradicate yaws and reduce child mortality in certain settings are cost-effective. But studies from 2005 and 2010 indicate that this would not be the case for the control and treatment of trachoma17, 18, 21. The proposal to periodically mass administer azithromycin to reduce child mortality is however questionable given that its precise mechanism of action is unclear, and that evidence of efficacy is somewhat mixed. However, the primary purpose of this paper is not to discuss this evidence, but to rather examine the MDA of antibiotics through a wider public health and health systems lens. In doing so, two broad issues stand out.
The first issue concerns the manner in which MDA programmes are funded, conceptualised, organised and implemented, and how they are situated within the context of longstanding tensions between differing approaches to health improvement in LMICs. While vertically managed and dedicated MDA programmes allow for focused, rapid and effective delivery, when they are conceived and constructed as single-focused interventions that are delivered through centralised and vertical structures, there is a risk that they may undermine other health services and more comprehensive and holistic approaches to health and lower the overall efficiency of the health system. For example, they can draw resources and attention away from other health services, and they can add to the fragmentation and duplication of efforts across the health system47, 48, especially if there are other vertical programme, which may be associated with higher total expenditures49.. MDA programmes and their focus on antimicrobials may also reinforce a mindset that privileges or exalts the superiority of biomedical interventions over the more messy social, political and economic pathways to health improvement.
Although MDA programmes can be a component of a comprehensive and holistic approach to the prevention and treatment of infectious diseases and improved child survival, they may also be used as an excuse or alibi for the lack of progress made in reducing poverty, extending access to clean water and sanitation, improving infant and child nutrition and ensuring universal access to comprehensive maternal and newborn care. Worse still, they could even divert attention and resources from upstream interventions that might produce more sustainable and long-term benefits50.
Other PHIs that are ‘mass administered’ share similar tensions. For example, while water fluoridation reduces the prevalence and incidence of dental caries51 and has a disproportionately beneficial impact on children from lower socio-economic groups52, it may have shifted dental public health attention away from the underlying causes of dental caries such as excessive sugar consumption and poor dental hygiene53. Similarly, VAS may bypass the underlying causes of vitamin A deficiency such as poor hygiene and poor diet54.
Tensions have long existed between approaches that give differing degrees of emphasis to selectivity as opposed to comprehensiveness, or to biomedicalism as opposed to social medicine, or to centralised and top-down vertical delivery systems as opposed to decentralised, bottom-up and integrated systems. Importantly these tensions cannot be resolved through evidence or science as they partly reflect different philosophical and ideological positions, whilst also adopting different timeframes. However, it is important that those funding, studying and advocating MDA programmes are open to discussing these tensions, and to seeking optimal integration and positive synergy with other interventions and services that may also reduce morbidity and mortality.
Importantly, WHO’s current advice that the MDA of azithromycin as a non-specific child survival strategy should only be considered in places where the IMR > 60 automatically means that it will be implemented in conditions where the rights of children to adequate nutrition and healthcare are not being universally met10. At present, 13 SSA countries have an IMR > 60: Burkina Faso, CAR, Chad, Ivory Coast, Eswatini, Guinea, Lesotho, Mali, Niger, Nigeria, Sierra Leone, Somalia, South Sudan55. However, there will be many sub-national geographies and populations in other countries with an IMR of more than 60. It remains unclear if such areas should be identified and assessed as to whether an MDA programme would be appropriate.
It is notable that an increasing number of MDA programmes are now recommended by WHO or researchers. In addition to the three discussed in this paper, WHO guidelines on MDA exist for several non-bacterial diseases: malaria56, lymphatic filariasis57, onchoceriasis58, schistosomiasis59, Taenia Solium60, soil-transmitted helminths61 and foodbourne trematodiase62. Other MDA applications recommended by researchers include single-dose oral ciprofloxacin in areas prone to meningitis epidemics63; azithromycin to reduce genital chlamydia trachomatis infection64; and albendazole or mebendazole to pregnant women to reduce neonatal mortality65. When coupled with the prominence of various vertical and top-down selective health programmes that exist, such as the Global Fund and the Global Alliance for Vaccines and Immunisations, it could be argued that MDA programmes are part of a wider prevailing selective primary health care paradigm that is partly responsible for perpetuating the problems of weak, fragmented and under-resourced health systems47.
The second issue that stands out when examining MDA programmes through a wider public health lens is that of AMR. One prediction is that by 2050, AMR will result in 10 million additional deaths per year, with a disproportionately high burden in LMICs66. Therefore, evidence that the mass administration of antibiotics will do more harm than good is crucial. Meanwhile, progress in improving antibiotic stewardship has been slow and inadequate, especially in LMICs where antibiotic consumption is increasing in the context of poor clinical practice67, 68, inadequate regulation of pharmaceutical markets, and inadequate clinical and laboratory surveillance of AMR prevalence69.
The contribution that MDA programmes might make to the worsening of AMR is not known. Evidence exists that suggests azithromycin MDA may lead to a degree of macrolide and nonmacrolide resistance, however the clinical and public health relevant of such resistance is currently unknown and clearly warrants further research39, 40, 70. Despite this, the guidelines discussed above appear to downplay the risk of worsening AMR6–10. For example, they do not recommend that a situation analysis of current patterns of antibiotic use or of levels of AMR is conducted prior to implementing an MDA programme.
The two issues raised here may be described as unintended consequences (UCs) associated with MDA programmes. Importantly, UCs associated with public health interventions (PHIs) tend to be neglected in the academic literature because relative to the UCs of clinical interventions, they are harder to detect and to attribute directly to the effects of PHIs71 and because many UCs associated with PHIs are second- or third-order consequences that are hard to anticipate72, 73. UCs may also be neglected or ignored by policymakers and researchers because of a general unwillingness to engage with uncertainty or to acknowledge gaps in knowledge71. Thus the hard data on the impact that MDA programmes might have on the incidence of disease or the saving of lives will tend to have more sway over the unknown potential (and longer term) harms arising from UCs, even if those harms may be considerably greater than the benefits.