With a little help from my friends
This analysis exploring the impact of ivermectin on fertility in Africa was conducted by my friend Mike Austin.
The data are derived from the Our World in Data (OWID) database and the WHO African Programme for Onchocerciasis Control (APOC) Final Evaluation Report published in October 2015.
Mike notes that before Ivermectin was introduced in 1987, countries beginning to use it already had a higher fertility rate than the others by a factor of 1.328. The relative fertility of ivermectin countries to non-ivermectin countries has been normalised at 1987 using this factor.
What the graphs show
Ever since its introduction, ivermectin countries have had greater fertility than non-ivermectin countries.
From 1987 to 1997, ivermectin was increasingly used in Africa. This was accompanied by an increase in fertility above non-ivermectin countries. The APOC programme started in 1997. Shortly after this, the rate of increase in relative fertility began to roll off and peaked in 2002 at about 1.35.
From 2002 to 2013, the rate of increase in relative fertility reduced. In 2013, the APOC programme stopped. Shortly after this, the relative fertility no longer continued to reduce. It levelled off to about 1.15, where it remains at the moment (2023).
Conclusion
From these observations, there is no evidence that ivermectin reduces fertility. In fact the evidence is to the contrary. The use of ivermectin has always been accompanied by an increase a country’s fertility rate above countries that do not use it. This is currently 15% higher, although it peaked at 35% higher in 2002.
It should be noted that, when the WHO’s APOC programme was in operation, the gains in greater fertility dropped back from the 2002 peak. This is clearly not due to ivermectin, which had already been accompanied with fertility gains. It may have more to do with how the WHO implemented their programme and/or whether they introduced other influencing factors at the time, such as injectable contraceptives.
Very interesting, thanks Mike!
References
- List of countries taking ivermectin for onchocerciasis fromhttps://doi.org/https://doi.org/10.1101/2021.03.26.21254377
- Our World in Data (OWID) databasehttps://ourworldindata.org/population-growth
- The WHO African Programme for Onchocerciasis Control (APOC) Final Evaluation Report, October 2015.https://iris.who.int/handle/10665/275724
A farmer friend in South Africa just sent me this message on Telegram:
Since 1987, we, the livestock farmers in SA, have always used ivermectin at the start of the breeding season to boost fertility of breeding herds. One study I read showed an improvement from 25% to 56% in maiden heifers treated with ivm! So, as usual, this [narrative that ivermectin caused infertility] is bullshit.
Bullshit, huh?
Well, she said it, not me and, as a farmer, she should know ;).
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