reminder: if you're getting an intramuscular injection (e.g. a covid booster or flu shot) and you're above 200 lbs with estrogen-based body fat distribution or 260 lbs with testosterone-based body fat distribution, you should be requesting a 1.5-inch/38mm needle. you might want to print out this sheet and bring it with you, because I have had pharmacy employees blithely tell me the 1-inch needle is fine for everyone, and I find a clear directive from the CDC just makes life a little easier.
(this is one major reason why obesity is associated with so many negative health outcomes, btw—shit is not designed for us and providers are not educated about our needs, so we have to educate ourselves about appropriate care and then make special requests to receive that care just to get to the baseline chances of success straight-sized people have by default.)
thabk you so much "the cdc recommends" were magic words and they were absolutely gonna use a standard 1" on me
For the methodology queens:
A long shot: The importance of needle length in vaccinating patients with obesity against COVID-19 (2022)
When should a longer needle be used for intramuscular injection in obese patients? A combined analysis of New Zealand data (2023)
Reuters Health: For obese, vaccine needle size matters (2010)
Accelerated waning of the humoral response to COVID-19 vaccines in obesity (2023)
Reblogging for the actual data. I would say that gauging (ha, ha!) needle length purely on body weight is... not ideal. If you're a 6'10" woman who weighs 200lbs... likely you'll need a shorter needle, not a longer one. However any other value is equally difficult to standardize - arm girth would encapsulate fat and muscle alike. The goal is (as the first link, to PubMed, explains) to adequately deposit the vaccine in the deltoid muscle. The variance is how much subcutaneous tissue you're penetrating. If you are aware you carry more subcutaneous fat in the deltoid region, by all means, bring the CDC guidance along! Advocate for yourself! EQUALLY, if you're within these weight guidelines but have very thin arms... this is a dialogue to have with the vaccine provider.















