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Here are those references and citations for the masochists among us!

https://www.nbcnews.com/health/health-news/childhood-vaccines-adults-booster-shots-measles-texas-what-know-rcna193197

https://pubmed.ncbi.nlm.nih.gov/36935110/

https://www.cdc.gov/vaccines/vpd/mmr/hcp/recommendations.html

https://pmc.ncbi.nlm.nih.gov/articles/PMC8189124/

https://www.cedars-sinai.org/newsroom/measles-makes-a-comeback-what-parents-need-to-measles-makes-a-comeback-what-parents-need-to-know/

https://www.npr.org/sections/shots-health-news/2025/02/21/nx-s1-5304458/measles-vaccine-booster-health

https://pmc.ncbi.nlm.nih.gov/articles/PMC6970218/

https://doh.wa.gov/sites/default/files/legacy/Documents/Pubs/348-479-MeaslesReferenceforProviders.pdf

https://www.who.int/news-room/fact-sheets/detail/measles

https://www.who.int/teams/immunization-vaccines-and-biologicals/diseases/measles

https://www.cdc.gov/vaccines/vpd/mmr/public/index.html

https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciae537/7874423

https://pmc.ncbi.nlm.nih.gov/articles/PMC7343595/

https://www.npr.org/2025/02/20/nx-s1-5302542/as-measles-cases-rise-its-not-just-kids-who-need-vaccines-some-adults-do-too

https://www.medrxiv.org/content/10.1101/2024.04.18.24306028v1

https://www.healthychildren.org/English/safety-prevention/immunizations/Pages/Protecting-Your-Baby-from-a-Measles-Outbreak-FAQs.aspx

https://pmc.ncbi.nlm.nih.gov/articles/PMC6414234/

https://news.uchicago.edu/big-brains-podcast-why-measles-resurging-and-rise-vaccine-hesitancy

https://www.ama-assn.org/delivering-care/public-health/long-covid-news-measles-texas-rsv-vaccine-moms-food-recalls-and-rural

https://www.news-medical.net/news/20240927/Study-shows-gradual-waning-of-MMR-vaccine-effectiveness-over-time.aspx

https://www.dshs.texas.gov/vaccine-preventable-diseases/vaccine-preventable-disease-conditions/measles-rubeola

https://www.science.org/doi/10.1126/science.aay6485

https://pmc.ncbi.nlm.nih.gov/articles/PMC6363159/

https://publichealth.jhu.edu/2025/what-to-know-about-measles-and-vaccines

https://www.dshs.texas.gov/news-alerts/measles-outbreak-feb-25-2025

https://www.khou.com/article/news/measles-booster-mmr-vaccine/285-553bfd35-a0d4-43a5-a4b7-9b22f9c22f51

https://www.cbsnews.com/news/measles-vaccine-booster-what-to-know/

https://www.houstonchronicle.com/news/houston-texas/trending/article/measles-vaccine-texas-outbreak-booster-20187132.php

https://www.pbs.org/newshour/show/west-texas-measles-outbreak-spreads-amid-vaccine-hesitancy-in-some-communities

More Citations:

https://www.news-medical.net/news/20240927/Study-shows-gradual-waning-of-MMR-vaccine-effectiveness-over-time.aspx

https://academic.oup.com/ofid/article/7/11/ofaa505/5932400

https://whyy.org/articles/measles-vaccine-booster-health/

https://pmc.ncbi.nlm.nih.gov/articles/PMC6970218/

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2782431

https://www.cidrap.umn.edu/measles/news-scan-sep-02-2020

https://www.nature.com/articles/s41467-023-37407-x

https://pmc.ncbi.nlm.nih.gov/articles/PMC10768653/

https://www.nbcnews.com/health/health-news/childhood-vaccines-adults-booster-shots-measles-texas-what-know-rcna193197

https://pmc.ncbi.nlm.nih.gov/articles/PMC8189124/

https://www.scielo.br/j/rimtsp/a/GvmM9bGk9GbtJxRJ674YHQn/

https://pubmed.ncbi.nlm.nih.gov/36935110/

https://pmc.ncbi.nlm.nih.gov/articles/PMC11663438/

https://pubmed.ncbi.nlm.nih.gov/35417025/

https://www.bmj.com/content/340/bmj.c1626

https://www.npr.org/sections/shots-health-news/2025/02/21/nx-s1-5304458/measles-vaccine-booster-health

https://www.medrxiv.org/content/10.1101/2024.04.18.24306028v1

https://pubmed.ncbi.nlm.nih.gov/39712819/

https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0170257

https://www.ama-assn.org/delivering-care/public-health/long-covid-news-measles-texas-rsv-vaccine-moms-food-recalls-and-rural

https://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm

https://www.healthdata.org/research-analysis/library/evaluating-scope-and-bias-population-level-measles-serosurveys

https://academic.oup.com/ofid/article/11/1/ofad700/7505490

https://academic.oup.com/jid/article/206/10/1542/858893

https://journals.asm.org/doi/10.1128/mbio.02628-20

https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(24)00181-6/fulltext

https://jamanetwork.com/journals/jamapediatrics/fullarticle/569784

https://academic.oup.com/jid/article/226/7/1127/6568034

https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciae537/7874423

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30442-4/abstract

Even More Citations:

https://hhs.iowa.gov/center-acute-disease-epidemiology/epi-manual/reportable-diseases/measles/controlling

https://www.chfs.ky.gov/agencies/dph/dehp/idb/Documents/KDPHMeaslesInvestigationGuide.pdf

https://www.cdc.gov/vaccines/vpd/mmr/public/index.html

https://www.healthychildren.org/English/safety-prevention/immunizations/Pages/Protecting-Your-Baby-from-a-Measles-Outbreak-FAQs.aspx

https://doh.wa.gov/sites/default/files/legacy/Documents/Pubs/348-479-MeaslesReferenceforProviders.pdf

https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/Immunization/Measles-Quicksheet.pdf

https://www.cdc.gov/vaccines/vpd/mmr/hcp/index.html

https://www.health.state.mn.us/communities/ep/han/2024/aug22measles.pdf

https://www.cdc.gov/vaccines/vpd/mmr/hcp/recommendations.html

http://publichealth.lacounty.gov/acd/procs/b73/DiseaseChapters/B73Measles.pdf

https://www.immunize.org/wp-content/uploads/catg.d/p4209.pdf

https://cdphe.colorado.gov/diseases-a-to-z/measles/measles-vaccination-recommendations

https://publichealth.jhu.edu/2025/what-to-know-about-measles-and-vaccines

https://kingcounty.gov/en/dept/dph/health-safety/disease-illness/measles/vaccine

https://www.immunize.org/ask-experts/topic/mmr/

https://libguides.mskcc.org/publichealth/MMRvaccination

https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/Immunization/HCWIZRecs.pdf

https://www.oregon.gov/oha/ph/DiseasesConditions/DiseasesAZ/Measles1/MeaslesVacRecom.pdf

https://www.npr.org/sections/shots-health-news/2025/02/21/nx-s1-5304458/measles-vaccine-booster-health

https://vaccine-schedule.ecdc.europa.eu/Scheduler/ByDisease?SelectedDiseaseId=8&SelectedCountryIdByDisease=-1

https://www.chop.edu/news/health-tip/measles-outbreak-how-protect-your-family

https://www.cdc.gov/measles/hcp/vaccine-considerations/index.html

https://www.dshs.texas.gov/news-alerts/measles-exposures-central-south-central-texas

https://www.cdc.gov/measles/vaccines/index.html

https://publications.aap.org/aapnews/news/31468/Nearly-100-infected-with-measles-amid-outbreak-in

https://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm

https://immunizationdata.who.int/global/wiise-detail-page/vaccination-schedule-for-measles

https://pmc.ncbi.nlm.nih.gov/articles/PMC8189124/

https://www.health.state.mn.us/diseases/measles/hcp/control.html

https://www.michigan.gov/-/media/Project/Websites/mdhhs/Folder3/Folder46/Folder2/Folder146/Folder1/Folder246/Healthcare_Occ_Health_Measles_Guidance_3-28-19_FINAL.pdf?rev=06be3f7b25dc4838ad9c3f04497ae2ab

https://www.middlebury.edu/measles/proof-immunity-requirements-and-examples

https://www.cbsnews.com/news/measles-vaccine-booster-what-to-know/

https://www.cdc.gov/measles/travel/index.html

https://www.aafp.org/family-physician/patient-care/prevention-wellness/immunizations-vaccines/disease-pop-immunization/measles-vaccine.html

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My IgG antibody from 2019 was borderline low positive. The PA that wrote back said I was either exposed or had immunization, but 2 emails later still hasn’t addressed if that means waning antibody protection and whether to boost or not.

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Yeah, it's tough to read between the lines, right? Half of the reason I did these two posts was to brush up on my own knowledge and ability to advise people. Personally I'm tempted to get titers drawn and boost if low since I'm in primary care, and people come in sick with all kinds of stuff and don't mask despite our requests to do so. Just yesterday two people I saw who ended up testing + for Flu A for example, and frowned at me for asking them to mask while in the office before their tests came back positive. I digress, just saying I hear you. despite all the above there is still some wiggle room for interpretation...

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The "lines" are testing my anxiety level, so I'll probably go ahead and get boosted to try and be on the safe side (Is there one???) Between Covid, Flu, H5N1, measles and the mystery illness in the Congo, I'm just not sure anymore...PS: It's good you made them mask, stay safe :)

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I have overdue labs I need to do as a patient myself, so I might do the same. These are incredibly stressful times compared to say, the 90’s. I don’t see humanity having time to catch its breath and reflect on history from here on out. It’s just full acceleration (off a cliff?). Still trying to enjoy that ride, breathless as it is.

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Thank you for this, Ryan. A public service.

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Welcome, Mara :)

Do you recall the Philly outbreak back in the day? Not sure if you were around here then.

There was also another one at Rutgers while I was a freshman, and vaccination was compulsory for all the students. I really vaguely recall getting exempted b/c I had the Philly MMR like 3 years prior.

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Yes, Ryan, this deeper dive is worth it for me. I have four siblings, born between 1953 and 1965, and we have no record of our MMR vaccinations and dim memories of measles infections. I’m pretty sure my nieces and nephew are vaccinated, but maybe not. I’m sharing this substack with all of them, so they can decide how to move forward.

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OK I'm glad Liz! It's written on two levels, so hopefully it helps beyond the usual. those dates of birth overlap the tricky, confusing years. I guess follow linked CDC guidelines like a cookbook, and when in doubt get a boost?

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Exactly. I’m in doubt, plus I’m in Texas. Far from Lubbock but, hey, it’s Texas. I just messaged my PCP to request a titer test, and if my immunity is low, an MMR boost.

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Spouse was born in 1965 and has no idea what he got so we are just going to get him vaccinated. I had the measles as a kid. And then my medical school made me get vaccinated in 1990 since I had no proof of vaccination. I am set. Measles: zero stars, do not recommend.

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Sounds right, Donna, thanks for the case presentation. Measles absolutely gets zero stars! Can we please close that place down!? Good luck. I'm hoping this settles down, but I am a little concerned about general immune system degradation from Covid illnesses. Will have to see if that black swan enters the discussion/data. Don't want to speculate or fearmonger at this time.

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Thank you for this deep dive. I appreciate it! I was born in 1964 and while I am sure my parents vaccinated me, I have no records. So have scheduled a booster just to be safe. Checked to make sure my tetanus shot was current, too.

Now just hoping RFK will allow flu shots next year ...

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Sounds about right MTB, good luck! I had a TDAP last year, too. I thought it was good to get the added pertussis protection beyond the simple Td, what with all the whooping cough going around the US and Europe (and beyond) these past 1-2 years

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I appreciate your effort to bring us this granular level of information. Thanks!

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Thanks Dar! I swear I'll drop some poetry as a palate cleanser (or emetic) soon!

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I think this is an impressive blend of original writing, research, experience, personal story, and perplexity deployment. The questions we ask, the phrasing, and the double checking of sourced references is becoming a modern day skill set. Like since 2023! Nice. Thanks for a great read for readers of different motivational levels.

Forwarding, and digging out my vaccine records now...

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Thanks Grant! I think you've summed up the skill set that is evolving right now. While I do mostly all original, human brain derived writing, there are truths and nuances to be hashed out in the inscrutable LLM mind for deep research questions. As long as we are qualified to review these insights like editors/peer-reviewers, and diligent about checking the transparent sources cited, this kind of writing has a necessary place alongside the traditional. I'll throw a dash in only when needed. Good luck finding those records!

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I am so glad you are a masochist so we mere mortals don’t have to be! Truly, you are a national treasure. While I was one who did not read all the technical detail, I appreciated the clarity of your explanations and summary and deeply appreciate having the rest at hand should I need to look further if the occasion demands. Thank you, thank you, thank you!

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Thank you Susan! You are just too kind and generous with your comment here! By the way, is that a new profile picture? It looks like a really cool cafe or something, a place I would like to set up with a friend and have lunch with coffee or a glass of white. Is that a favorite haunt of yours?

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It is definitely a really cool cafe, and I wish it were closer by! It is the Martinho da Arcada in Lisbon, a favorite haunt of Fernando Pessoa’s. I am sitting in a corner decked out with Pessoa paraphernalia. It turned out, when I tried to find a decent profile photo, that all the passable options were vacation photos!

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My daughter and her husband and 3 month old baby are coming to visit from the UK this month - to California.

My question is - baby won’t have had vaccine for Measles yet - does mom need to check her levels of immunity or because they are traveling internationally to now the US - and does her immunity pass through her breast milk?

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Hi Sally - the outbreak is not that big at the moment, though who knows. I can;t give her any specific advice without her being my patients, but I was able to find this general information...

Newborns receive passive immunity against measles from their mothers, but by 3 months of age, this protection has significantly declined.

For babies whose mothers have natural immunity from having had measles, passive antibodies typically protect the infant for about 5-6 months, though protection begins decreasing after birth. By 3 months, these babies still have some protection, but it's waning.

For babies whose mothers have vaccine-induced immunity (which is more common today), the protection is shorter-lasting. These infants have lower initial antibody levels and may only be protected for about 2-3 months. At 3 months old, many of these babies have minimal remaining protection.

This declining maternal immunity is why measles outbreaks can be particularly dangerous for infants too young to receive their first MMR vaccine (typically given at 12-15 months). In high-risk situations or during outbreaks, doctors sometimes recommend an early dose of the measles vaccine for infants as young as 6 months.

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And baby will be around one year old cousin who hasn’t been vaccinated as well - I guess there could be concrete there as well. Thanks so much for your information - it really does matter to me!!

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Wonderful post. thank you. As someone born slightly before 1957 (and a skeptic) I am suspicious of the capability of this birth year to differentiate the immune without vaccination from those who should be vaccinated.

Canada uses 1970 (https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-12-measles-vaccine.html#)

and the UK doesn't have a birth year cut-off .

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Hi - great points, and now more than ever is a good time to check outside the CDC box with respect to other prestigious institutional/consensus guidelines. Better to err on the side of caution with measles is what I'm reading, right?

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Wow--thank you so much for this late-night effort and providing the references. I am an epidemiologist and will be taking a deeper dive. Could you clarify the recommendation re booster for those born during 1957. Are these folks considered in the after 1957 group that should consider a booster?

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Hi Carole. Thanks for the question, and I will preface my answer by saying that as an epidemiologist, feel free to give me come counterpoints. But my understanding goes like this:

The CDC generally considers people born before 1957 to have presumptive immunity to measles, mumps, and rubella. This is because these diseases were so widespread before vaccines were available that most people were infected during childhood. By the time measles vaccination began in 1963, most Americans had already had natural measles infections.

For this reason, the CDC does not routinely recommend MMR vaccination for adults born before 1957. These individuals are presumed to have lifelong immunity from natural infection.

However, there are some exceptions:

Healthcare personnel: The CDC recommends that healthcare workers born before 1957 without laboratory evidence of immunity or disease should consider getting 2 doses of MMR vaccine during an outbreak.

During outbreaks: Local health departments might recommend that people born before 1957 in affected communities get vaccinated during an outbreak.

International travel: In some cases, vaccination might be recommended for international travelers born before 1957 who don't have other evidence of immunity.

Women planning pregnancy: Women of childbearing age, regardless of birth year, should ensure they're immune to rubella before pregnancy.

If someone born before 1957 wants to confirm their immunity status, they can get a blood test to check for antibodies, although this isn't routinely recommended.

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Thanks, I have been pondering this in my mind given my history. One reason is is the phenomenon of Immunity Senescence or immunosenescence (high risk?)

I need to see more on Immune Amnesia I covered last time. Maybe this will still be migrated without the booster? I think if this was covered more by the CDC and other Health authorities, it may help the lag in vaccination? Unfortunately, jr is standing in the way. Beginning to wonder if we will have flu vaccines this Fall.

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all good questions KB, and when in doubt get more data with either titers or an empiric boost? "Talk to your doc" as they say, and yes, WTAF regarding flu shots for next year. That should be medical malpractice and we need to start treating this as such. Know any pro-bono types who are not already fighting 100 good fights?

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This science-minded senior (b. 1946) so appreciates your explanation of the nuances, Ryan!

VERY grateful for you!! (How could I not be a paying subscriber?!)

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Thank you Terry!!!

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Ryan, your efforts to keep us well informed are truly heroic. Please take better care of yourself, and get more sleep!

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