The Nonlinear Library EA - Malaria vaccines: how confident are we? by Sanjay
Jan 5, 2024
19:58
Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Malaria vaccines: how confident are we?, published by Sanjay on January 5, 2024 on The Effective Altruism Forum.
Alternative title: should SoGive red-team malaria vaccines?
We've been seeing a lot of excitement about malaria vaccines - e.g. the first thing mentioned by the
EA wins 2023 post was the R21 vaccine.
We at SoGive looked into malaria vaccines about a year ago, and came away with a slightly more cautious impression. Bear in mind though, (a) we were trying to answer a different question[1]; (b) a lot has changed in a year.
The purpose of this post is to outline these (currently tentative) doubts, and explore whether there's appetite for us to research this more carefully.
The main things we're still unsure of
At first glance, malaria vaccines appear less cost-effective than existing malaria interventions (nets/SMC[2]). Are they, in fact, less cost-effective?
In light of this, does it make sense to advocate for their rollout?
We thank 1Day Sooner for their helpful comments and constructive collaboration - we sent them a draft of this shortly before publishing. We also thank our contacts at Malaria Consortium and AMF; when we spoke to them in 2022 for our earlier review of malaria vaccines, their comments were very helpful. Some earlier work done by current/former members of the SoGive team has also provided useful groundwork for the thinking here, so thank you to Isobel Phillips, Ishaan Guptasarma, Scott Smith.
Be aware that any indications of cost-effectiveness in this post are extremely rough, and may change materially if we were to conduct this research.
Malaria vaccines may be materially (10x??) less effective than nets/SMC
Based on the research we did a year ago, it seems that malaria vaccines significantly underperform bednets and SMC. Several items in this table are caveated; it's worth reviewing the version in the appendix which sets out the details.
Several items in this table are caveated; it's worth reviewing the version in the appendix which sets out the details.
RTS,S vaccine
R21 vaccine
Bednets*
Cost-related considerations
Cost per person treated
$56.40 (estimated)
>$8, based on WHO info; ~$25, based on info from 1Day Sooner
$2.18
Number of doses needed per person
4 (i.e. 3 + a booster)
4 (i.e. 3 + a booster)
0.49 bednets per person protected
Logistics: cold chain?
Yes
Yes, but less demanding than RTS,S
No
Efficacy-related considerations
Reduction in clinical malaria**
55.8%
77%
45%
Reduction in severe malaria**
32.2%
Unknown, estimated at 44.4%
45%
* SMC is only excluded from this table for brevity, not because of any preference for bednets over SMC.
** Malaria reduction figures are estimates under study conditions
Vaccine costs look high…
When we created this table c.1 year ago, the key message from this table is that costs for vaccines are materially higher than for bednets or SMC, which is significantly driven by logistical difficulties, such as the need for multiple doses and a cold supply chain (i.e. the vaccines have to be kept at a low temperature while they are transported). At the time, we focused on RTS,S because there was more information available.
At that stage, we guessed that R21 would likely have similar costs to RTS,S. Somewhat to our surprise, it does seem that R21 costs may be lower than RTS,S costs. We weren't clear on the costs of R21, however when we shared a draft of this with 1Day Sooner, they helpfully pointed us to their
Dec 2023 Vaccination Status Report. It seems they believe that each dose costs $3.90 on its own, and the all-in cost of delivering the first dose to a person is $25 per full course.
... and there doesn't * seem * to be an offsetting efficacy benefit.
Although the efficacy numbers look similar, there are several complicating factors not captured in this table. For example, a consideration about the ages ...
Alternative title: should SoGive red-team malaria vaccines?
We've been seeing a lot of excitement about malaria vaccines - e.g. the first thing mentioned by the
EA wins 2023 post was the R21 vaccine.
We at SoGive looked into malaria vaccines about a year ago, and came away with a slightly more cautious impression. Bear in mind though, (a) we were trying to answer a different question[1]; (b) a lot has changed in a year.
The purpose of this post is to outline these (currently tentative) doubts, and explore whether there's appetite for us to research this more carefully.
The main things we're still unsure of
At first glance, malaria vaccines appear less cost-effective than existing malaria interventions (nets/SMC[2]). Are they, in fact, less cost-effective?
In light of this, does it make sense to advocate for their rollout?
We thank 1Day Sooner for their helpful comments and constructive collaboration - we sent them a draft of this shortly before publishing. We also thank our contacts at Malaria Consortium and AMF; when we spoke to them in 2022 for our earlier review of malaria vaccines, their comments were very helpful. Some earlier work done by current/former members of the SoGive team has also provided useful groundwork for the thinking here, so thank you to Isobel Phillips, Ishaan Guptasarma, Scott Smith.
Be aware that any indications of cost-effectiveness in this post are extremely rough, and may change materially if we were to conduct this research.
Malaria vaccines may be materially (10x??) less effective than nets/SMC
Based on the research we did a year ago, it seems that malaria vaccines significantly underperform bednets and SMC. Several items in this table are caveated; it's worth reviewing the version in the appendix which sets out the details.
Several items in this table are caveated; it's worth reviewing the version in the appendix which sets out the details.
RTS,S vaccine
R21 vaccine
Bednets*
Cost-related considerations
Cost per person treated
$56.40 (estimated)
>$8, based on WHO info; ~$25, based on info from 1Day Sooner
$2.18
Number of doses needed per person
4 (i.e. 3 + a booster)
4 (i.e. 3 + a booster)
0.49 bednets per person protected
Logistics: cold chain?
Yes
Yes, but less demanding than RTS,S
No
Efficacy-related considerations
Reduction in clinical malaria**
55.8%
77%
45%
Reduction in severe malaria**
32.2%
Unknown, estimated at 44.4%
45%
* SMC is only excluded from this table for brevity, not because of any preference for bednets over SMC.
** Malaria reduction figures are estimates under study conditions
Vaccine costs look high…
When we created this table c.1 year ago, the key message from this table is that costs for vaccines are materially higher than for bednets or SMC, which is significantly driven by logistical difficulties, such as the need for multiple doses and a cold supply chain (i.e. the vaccines have to be kept at a low temperature while they are transported). At the time, we focused on RTS,S because there was more information available.
At that stage, we guessed that R21 would likely have similar costs to RTS,S. Somewhat to our surprise, it does seem that R21 costs may be lower than RTS,S costs. We weren't clear on the costs of R21, however when we shared a draft of this with 1Day Sooner, they helpfully pointed us to their
Dec 2023 Vaccination Status Report. It seems they believe that each dose costs $3.90 on its own, and the all-in cost of delivering the first dose to a person is $25 per full course.
... and there doesn't * seem * to be an offsetting efficacy benefit.
Although the efficacy numbers look similar, there are several complicating factors not captured in this table. For example, a consideration about the ages ...