I'd like to alert you all to a new publication called "Occupational health outcomes among sanitation workers: A systematic review and meta-analysis". It came out in March 2022 in the International Journal of Hygiene and Environmental Health and is not behind a paywall which is great:
www.sciencedirect.com/science/article/pii/S1438463921002224

I was actually alerted to it while browsing the blog posts of the Sanitation Workers Knowledge and Learning Hub. One of their recent blog posts gives an easy to read overview of the publication. You can find it here: sanitationworkers.susana.org/blog/10-san...a-global-perspective
Title: "Sanitation workers’ health: a global perspective"
Jen Barr, PhD, MPH | August 2022

The key take-aways of the publication as summarised in the blog post are: 

1. A team from Emory University and the World Health Organization published a literature review examining health outcomes of sanitation workers in the 2022 International Journal of Hygiene and Environmental Health. 
2. Given the working conditions and the potential exposures to hazardous materials, understanding the exact risks that sanitation workers are exposed to is vital in improving their wellbeing. 
3. For most health outcomes, there aren’t enough high-quality studies that use similar enough methods to clearly estimate the risks to workers.  
4. The clearest evidence for sanitation workers suffering disproportionately negative effects compared to other groups is for gastrointestinal conditions and respiratory problems.   
5. While most parts of this field need significantly more study, the three populations identified by the literature review that need the greatest amount of work yet are women, informally employed workers, and workers in low-income nations.  

I found the blog post and publication very interesting. What struck me from the publication was this statement:

"Finally, we identified no studies that describe the working conditions or the burden of disease faced by sanitation workers who are informally employed, another clear gap in the current research."

This means their reported health impacts are likely to be an underestimation of the real burden of diseases. I think it's fair to assume that the informally employed sanitation workers will suffer even more health impacts than the formally employed workers.

Do any of you have an opinion about this publication or have knowledge to share on the topic of health outcomes for formally or informally employed sanitation workers?

Due to the fact that the journal publication is open access, I was easily and quickly able to utilise some of its content to update and enrich the Wikipedia article on sanitation workers in the section on Challenges / Occupational safety and health /Estimating occupational health outcomes among sanitation workers:

en.wikipedia.org/wiki/Sanitation_worker#...al_safety_and_health

Estimating occupational health outcomes among sanitation workers
It is difficult to estimate the burden of disease associated with occupational exposure to sanitation work due to the lack of clarity about the health risks and the uncertainty about the number of persons exposed. ^[4]  A systematic literature review with 65 studies showed the following: There was an increased risk of adverse health across a range of outcomes. This is especially true in the case of  hepatitis A  infections, where a pooled estimate from 13 studies showed a doubling of odds associated with sanitation work, and even higher odds when limited to studies with lower risk of bias. ^[4]

An increase in adverse gastrointestinal and respiratory conditions associated with sanitation work was also reported as the most common outcome. ^[4]  Comparatively few studies reported on adverse musculoskeletal and mental/social impacts, but these again consistently found elevated odds among sanitation workers. There was inconsistent evidence on mortality. ^[4]

There is a need for further investigation and quantification of the health risks faced by sanitation workers, as compared to workers in other occupations, particularly in low-income countries, and of the effectiveness of governmental policies and other efforts to mitigate these risks. ^[4]  There are research gaps in characterizing the health risks of sanitation workers in three main areas: low-income countries, among women and those under informal employment.

I've also tried to explain the distinction between different forms of employment of sanitation workers in the Wikipedia article like this: 
en.wikipedia.org/wiki/Sanitation_worker#Types_of_employment

3 Types of employment
Sanitation workers work in different types of employment situations. They are either government-employed workers, workers of private service providers or  informal workers . ^[10]  Sanitation workers who are employed by the government usually have comparatively good infrastructure, tools and personal protective equipment (PPE), and face only moderate health and safety risks. ^[11]

For example, the tasks of unclogging of the main sewers or operating  wastewater treatment plants  are usually performed by formal government workers or private companies, whereas the unclogging of household sewer connections is performed by private companies and informal sanitation workers. ^{[10] : 13}

3.1 Informal workers
In many developing countries, informal workers collect  human excreta  from certain types of toilet (such as  bucket toilets  and  pit latrines ) without mechanical equipment and without personal protective equipment. These workers are "scooping out feces from ‘dry’ latrines and overflowing pits". ^[12]  They are usually working in the informal labour sector and are commonly referred to as "informal sanitation workers". They have weak legal protection results from working informally and do not follow  occupational health and safety  standards. ^{[1] : 7}

Informal workers provide "manual emptying services to households, particularly where inaccessible to trucks and to the most vulnerable households". ^[11]  They are not registered or legally recognized, and often work without any protection, facing discrimination and stigma. ^[11]

Regards,
Elisabeth