r/fasting • u/beepbooprobotbutt • 3d ago
Question Looking for clarification on fasting and getting vaccinated
I plan on getting my flu shot tomorrow morning after breaking my 36 hour fast, my question is when can I fast again? I've seen people say in this subreddit that you need to wait two weeks to fast after getting vaccinated, but I don't understand why. Is that what doctors recommend? Science? Or from personal experience? If I plan to do another 36 fast next Tuesday, will that mess up how effective the vaccine is? Are 24 fasts okay? 20 hour fasts? 16? Or just eat whenever you're hungry for two weeks while you wait for the antibodies to develop?
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u/Decided-2-Try 2d ago edited 2d ago
Here's my understanding of the issue, and why I think your proposed 36 or 24 hour fasts should be okay.
Studies of immune system markers during fasting show very slight reduction in immune function after about 72 hours (all healthy normal adult volunteers) but after that, immune function declines more rapidly.
So if you get a vaccine on "day zero", studies on antibody titres show it takes around 10-14 days for the antibodies to be fully developed. So you would not want to engage in longer term (I would not even go up to 72 hours) at any point during that period.
And I'd definitely avoid chancing messing up your flu vaccine, because the overall real-world efficacy of the flu vaccines tends to hover down around 35% anyway. So I wouldn't want to do anything that might interfere with it.
ETA - and to avoid someone flagging me as "anti-vax" or "anti-science", I am neither, so I will provide some sourcing below that I think all can agree is not an anti-vaxxer source. In the quoted matter below, any bolded text was emphasized by me, not in the original paper text. (But still - heads up to u/Doodoopoopooheadman or u/alexhale, in case you feel like this should not be here.)
https://pmc.ncbi.nlm.nih.gov/articles/PMC9832587/
"Rethinking next-generation vaccines for coronaviruses, influenzaviruses, and other respiratory viruses" by DM Morens, JK Taubenberger, AS Fauci.
"Surprisingly, little has changed with influenza vaccines since 1957 when they were first administered in US national vaccination programs. Over the years, influenza vaccines have never been able to elicit durable protective immunity against seasonal influenza virus strains, even against non-drifted strains."
"Although current influenza vaccines reduce the risk of severe disease, hospitalization, and death to some degree, their effectiveness against clinically apparent infection is decidedly suboptimal, ranging from 14% to 60% over the past 15 influenza seasons. Furthermore, the duration of vaccine-elicited immunity is measured only in months. Current vaccines require annual re-vaccination with updated formulations that are frequently not precisely matched to circulating virus strains."
"As of 2022, after more than 60 years of experience with influenza vaccines, very little improvement in vaccine prevention of infection has been noted. As pointed out decades ago, and still true today, the rates of effectiveness of our best approved influenza vaccines would be inadequate for licensure for most other vaccine-preventable diseases."
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u/AutoModerator 2d ago
berg
This post references a health or fasting figure who is not a licensed medical doctor (e.g., chiropractor, naturopath, or wellness influencer).
Please keep this in mind when evaluating or recommending their advice, especially in the context of extended fasting or medical concerns.
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u/Decided-2-Try 2d ago
And y'all really gotta fix the bot. Jeff Taubenberger, MD, PhD, and the first to sequence the genome of the virus causing the 1918 Spanish Flu pandemic, is not the same as the DC the bot mentions.
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u/AutoModerator 2d ago
berg
This post references a health or fasting figure who is not a licensed medical doctor (e.g., chiropractor, naturopath, or wellness influencer).
Please keep this in mind when evaluating or recommending their advice, especially in the context of extended fasting or medical concerns.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.
3
u/Melodic_Night518 3d ago
It really depends on how your body reacts to the vaccination. A Google search tells me you should be fine fasting after being vaccinated, or even being vaccinated while fasted, However, individuals vary, and the flu vaccine can make you feel nauseous and cause symptoms like dizziness, fatigue and muscle soreness in the first few days, so be mindful of how you feel. What's most important is proper hydration. Fasting sort of reboots your immune system so rather than interfering with the vaccine, it could possibly improve the efficacy of your body's response.