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Sean Mullen, Ph.D. @drseanmullen.bsky.social

1/ Most people still don’t know how to use a rapid antigen test (RAT) correctly. So here’s a 🧵on how to get the most accurate results and avoid spreading COVID:

may 28, 2025, 10:43 pm • 451 259

Replies

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elypaul.bsky.social @elypaul.bsky.social

Sure would be nice to have a higher sensitivity, lower cost option like this- bsky.app/profile/atra...

may 29, 2025, 2:24 am • 26 3 • view
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Francien @francienh9.bsky.social

It could end the pandemic, if people would be willing to use these tests and isolate when positive.

may 29, 2025, 5:05 am • 27 0 • view
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Jen 🇸🇩🇵🇸 @harlickjen.bsky.social

But alas, brunch dates are more important for most people.

may 29, 2025, 12:24 pm • 16 1 • view
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Beth Morton @migrainechat.bsky.social

📌

may 29, 2025, 1:52 am • 1 0 • view
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L. Juniebird @juniebird.bsky.social

📌 thanks for the reminder!

may 29, 2025, 3:02 am • 2 0 • view
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Janet H @jehscribbler.bsky.social

📌

jul 2, 2025, 6:06 pm • 0 0 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

2/ 🟨 Any visible line, even faint or partial, is positive. Not "maybe." Not "inconclusive." Positive. Treat it that way. Stay home.

may 28, 2025, 10:43 pm • 162 20 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

3/ 🧪 Swab like you mean it. Use a multi-point method: – Cheeks – Under tongue – Back of tongue – Then low and slow into each nostril (aim toward throat, not up at brain). Don't just swirl boogers.

may 28, 2025, 10:43 pm • 154 24 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

4/ ⏱ Most people don’t test positive until Day 4 after exposure or symptoms. Test for 4 days in a row to catch it. One negative test ≠ you're in the clear. Infectiousness usually lasts 7+ days.

may 28, 2025, 10:43 pm • 157 32 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

5/ 🥤 Just like PCR, don’t eat or drink for 1 hour before testing—even if it’s not in your RAT instructions. That includes gum, brushing teeth, etc. It can mess with detection.

may 28, 2025, 10:43 pm • 157 20 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

6/ 🧬 RATs still detect current variants. But quality matters. Best? ✅ PCR or comparable, like PlusLife (if you can get it) which is 97+% effective ✅ European combo kits (SARS2 + Flu + RSV) Avoid sketchy off-brand kits with no approvals.

may 28, 2025, 10:43 pm • 135 10 • view
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Janet H @jehscribbler.bsky.social

📌

jul 2, 2025, 6:06 pm • 0 0 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

7/ Bonus: Test before gathering. Test again the day after. If you’re exposed, repeat testing Days 1-4 after. If you’re symptomatic, test for 3–4 consecutive days.

may 28, 2025, 10:43 pm • 130 10 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

8/ Bottom line: These guidelines aren’t new. They’ve been true since 2020. What changed? Not the science — just the will to listen. RATs can work, but only if you do them right. Most people don’t.

may 28, 2025, 10:43 pm • 174 19 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

9/ There is a new wave barreling right now in the US. We just aren’t tracking it. 📉 No data. 😷 No masks. 📚 Taiwan just went remote after more than doubling Emergency Department cases last week from ~20K to >40K. The virus hasn’t disappeared. Only the infrastructure to warn us has.

may 28, 2025, 10:43 pm • 427 177 • view
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Julie Haas @labhaas.bsky.social

Does "we're not tracking it" mean that wastewater data is suspicious?

may 28, 2025, 10:47 pm • 4 0 • view
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Willi Morris @williesha.bsky.social

This is also my question. I assumed wastewater data is still accurate.

may 29, 2025, 3:30 am • 6 0 • view
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Frannie, herself. @frannieoh.bsky.social

Context. www.aa.com.tr/en/health/co...

may 29, 2025, 4:54 am • 9 3 • view
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Frannie, herself. @frannieoh.bsky.social

www.independent.co.uk/news/health/...

may 29, 2025, 5:01 am • 2 0 • view
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Cancan12312 @cancan12312.bsky.social

Thanks for all these tips. Unfortunately, they’re too expensive for many people to test that much. And from what I’ve seen, stock is limited. I get the frustration. Public health is a vague shadow of its former self. 😔

may 28, 2025, 10:53 pm • 53 0 • view
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Kimberly #MaskUp Ratliff, MSc @kimberlyratliff.bsky.social

Contact your local Mask Bloc to see if they have tests on hand they can give you for free (and respirator masks too if you need them)! maskbloc.org Also call your local Public Health authority (city, county, state Dept of Health & Human Svcs).

may 28, 2025, 11:28 pm • 40 6 • view
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Michelle Ziemba @michelleziemba.bsky.social

Some manufacturers will sell directly to you at a cost that’s less expensive than a grocery or drug store. Less demand for tests have made them less expensive, too. If you can’t afford to test, you should be masking up.

may 28, 2025, 11:57 pm • 5 0 • view
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Francien @francienh9.bsky.social

Masks are less expensive (leave them out to dry and reuse them up to 48 hours total or when broken/difficult to breathe through) and more effective at preventing transmission. It is sad that there is so much resistance against masks.

may 29, 2025, 5:04 am • 9 0 • view
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😷 @eemser.bsky.social

📌

may 29, 2025, 4:48 am • 3 0 • view
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Otafuku3 @otafuku3.bsky.social

📌

jun 6, 2025, 7:19 am • 0 0 • view
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Felix W. @felixwe.bsky.social

seems important. The variant itself doesn't seem responsible for the surge of severe cases but the strong increase of cases. Like many other countries in the world, Taiwan lacked a major winter wave, leaving more people susceptible to reinfection. www.aa.com.tr/en/health/co...

CDC spokesperson Lo Yi-chun explained that while increased testing during the outbreak may have uncovered previously undetected cases, the main cause of the surge is the rapid spread of the virus. Lo noted that the new variant NB.1.8.1 has strong immune evasion abilities which allow it to bypass the body's existing defenses more easily, and is more transmissible than earlier variants. Additionally, Lo pointed out that the lack of a major outbreak during winter meant many people were not exposed to the latest variant and therefore lack immunity from natural infection.
may 29, 2025, 6:01 am • 2 0 • view
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Felix W. @felixwe.bsky.social

@chrischiu.bsky.social is there an official website to see the course of the pandemic/cases in Taiwan? thx!

may 29, 2025, 6:23 am • 0 0 • view
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Arizona Birder @liberalazbirder.bsky.social

I did not know about not eating or drinking within an hour of testing. Thank you for this information! 🥰

may 28, 2025, 10:45 pm • 3 0 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

It’s not really well known to be honest, but two things are true and everyone who works in a lab will confirm: 1. Some food and liquids will dilute your sample. 2. Some foods and liquids will temporarily kill virus (eg CPC mouthwash will kill it, briefly, if it’s actively replicating).

may 28, 2025, 10:53 pm • 3 0 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

People who simply follow the nasal instructions might ignore this, viewing it as irrelevant. But ignoring testing the oral cavity is going to miss infection, frequently.

may 28, 2025, 10:55 pm • 2 0 • view
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Arizona Birder @liberalazbirder.bsky.social

SO good to know! Thank you so much.

may 28, 2025, 10:54 pm • 1 0 • view
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Elana Levin @levin.bsky.social

I never tested positive on a RAT when I had Covid. Only in PCR. And yes I tested correctly

may 31, 2025, 4:08 am • 0 0 • view
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UsuallyquietinCanada @usuallyquietin.bsky.social

It does depend on the RAT, some of them are absolutely garbage: www1.racgp.org.au/newsgp/clini...

may 31, 2025, 5:21 am • 0 0 • view
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Elana Levin @levin.bsky.social

I used the best rated. Rats just aren’t accurate enough for anything after alpha. They never updated .

may 31, 2025, 5:22 am • 1 0 • view
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Lola C @kikigo007.bsky.social

Thank you for promoting science & best practices! I found this testing guidance in 2022 from Ontario Health after reading about swabbing oral & nasal cavities to get most accurate results. You’re advising best NOT to go so deeply with swab into nostrils? Thanks for clarifying

image
jun 13, 2025, 12:14 pm • 1 0 • view
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Kristin🇨🇦💉😷 @te4ch.bsky.social

I have a PlusLife and it saved us from gathering when a family member was pre-symptomatic, but now I can't buy them for import to Canada. 😞

may 29, 2025, 11:05 am • 1 0 • view
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Aussie who is not a rhino @badcustsvc101.bsky.social

This is the first reco I've seen for European tests. Are there any brands or sources of supply that you can suggest?

may 29, 2025, 12:08 am • 1 0 • view
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LGK @gevarticus.bsky.social

Any idea how to get a Pluslife to the US nowadays? Or should I just go right for the Metrix?

jul 1, 2025, 11:55 pm • 0 0 • view
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virus.sucks @virus.sucks

Use Metrix, it's fine. Pluslife is no longer available at all :(

jul 2, 2025, 3:13 pm • 1 0 • view
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Lizabeth @life2short16.bsky.social

yes, also wondering if you meant no longer available in U.S. only, or other countries as well?

jul 2, 2025, 5:57 pm • 1 0 • view
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Daniel Zeus Düsentrieb @3perf.bsky.social

bsky.app/profile/3per...

aug 31, 2025, 7:09 am • 1 0 • view
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Release & Embrace @releasembrace.bsky.social

No longer available anywhere in the world or just the US?

jul 2, 2025, 3:45 pm • 1 0 • view
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Daniel Zeus Düsentrieb @3perf.bsky.social

Apparently US. Still available here in Germany, and by extension, the whole EU. altruan.de/collections/... So if you're ever visiting, or have friends from the EU visiting you ... But don't forget that you also regularly require fresh tests. Their shelf life isn't huge.

aug 31, 2025, 7:08 am • 2 0 • view
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Release & Embrace @releasembrace.bsky.social

The tests have a shelf life of about a year. That’s great to know they are still available around the world even though the US is blocking access.

aug 31, 2025, 2:52 pm • 2 0 • view
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LGK @gevarticus.bsky.social

Darn. Thanks for letting me know.

jul 2, 2025, 3:23 pm • 1 0 • view
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Guay @guay.bsky.social

Smoking too

may 29, 2025, 12:35 am • 1 0 • view
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Cancan12312 @cancan12312.bsky.social

What about back of throat too?

may 28, 2025, 10:45 pm • 0 0 • view
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Sean Mullen, Ph.D. @drseanmullen.bsky.social

I mean, every time you swallow, the back of your tongue touches the back of your throat. So it seems redundant.

may 28, 2025, 10:49 pm • 0 0 • view
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DrNotta @drnotta.bsky.social

My tongue absolutely never touches my oropharynx, and if yours does you're at risk of pneumonia. The purpose of the epiglottis is to cover the respiratory opening while swallowing.

may 29, 2025, 12:12 pm • 1 0 • view
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Cancan12312 @cancan12312.bsky.social

Good point. 😃

may 28, 2025, 10:57 pm • 0 0 • view
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Eric Thee B @ericblanchard.bsky.social

But but but the directions don’t say to do this!

may 29, 2025, 2:28 am • 0 0 • view
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Rocket57 🇨🇦 @rocket57.bsky.social

Thanks for this breakdown. Is swabbing the back of the throat no longer a thing? It’d be a lot easier on my kids if that is the case! lol

may 29, 2025, 12:30 am • 1 0 • view
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Sushipink @sushipink.bsky.social

Do you have a source for this please? The stuff I have read before suggested that you should try not to touch your tongue, and a nurse friend told me that all the saliva will fill up the swab so that it doesn't take on any nasal material. I feel as though the guidance is conflicting/unclear

may 29, 2025, 2:44 am • 1 0 • view
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Un vrai loup, féroce et sanguinaire @footpad.bsky.social

I agree it'd be nice to have an authoritative opinion. Dr Mullen's CV makes me feel barely competent to even read the darn document (ahs.illinois.edu/sites/defaul...), so I won't invalidate his advice, but at least I'd say his primary expertise is elsewhere.

may 29, 2025, 6:34 am • 0 0 • view
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Sparrow @astralopithekos.bsky.social

I always do nose first and then mouth because the mouth is objectively "dirtier" (more bacteria etc). Is there any reason (with respect to accuracy of tests) to prefer the order you said?

may 29, 2025, 1:36 am • 2 0 • view
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this1girl is here too @this1wierdgirl.bsky.social

Except I'm one of the ones cursed with being able to see where the line would be before I even do the test. 😭 I want a digital one like those pregnancy tests.

may 31, 2025, 4:16 am • 0 0 • view
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AlyO @alyxiaoliviformis.bsky.social

📌

may 28, 2025, 11:17 pm • 2 0 • view
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Gwen Griffith-Dickson @ggriffith-dickson.bsky.social

📌 Proper use of covid test

may 29, 2025, 4:19 pm • 0 0 • view
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deetee1948.bsky.social @deetee1948.bsky.social

Since gov't health agencies are no longer addressing covid in any detail and MSM has bought into "it's no longer relevant or dangerous " - only a few of us are on guard. Thanks for keeping the information current!

may 29, 2025, 3:03 pm • 7 1 • view
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deetee1948.bsky.social @deetee1948.bsky.social

I caught covid only once because a friend who's a retired nurse assured me she tested negative - she didn't know she should swab her mouth - a full year after that was advised. Question everyone who says their negative!

may 29, 2025, 3:03 pm • 8 0 • view
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lesstravelled.bsky.social @lesstravelled.bsky.social

At this point, we don't trust rapids except with one family, and since we bring the pluslife, we watch ppl to make sure they swab right. So much of my family is resistant to the oral swab 🤦‍♀️

may 30, 2025, 4:08 am • 3 0 • view
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lmn24.bsky.social @lmn24.bsky.social

It’s so wonderful that your family is willing to swab to meet with you, even with resistance to oral swabs.

jun 8, 2025, 9:50 am • 1 0 • view
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Arizona Birder @liberalazbirder.bsky.social

I just put all this into my notes. Thank you so much! 🥰 Signed, a Novid Lone Masker in Arizona

may 28, 2025, 10:50 pm • 19 0 • view
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kitalderdice.bsky.social @kitalderdice.bsky.social

📌 excellent thread on Covid testing

may 31, 2025, 4:35 am • 4 0 • view
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🌷🌹Meli🏳️‍🌈 | Vtuber comms open/Gamba era @xbellezax.bsky.social

📌

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Kelanoa 😷 @kelanoa.bsky.social

📌

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📌

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📌

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R.E.L. @fancydancer.bsky.social

📌

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Gary Klama @klamarama.bsky.social

📌

may 28, 2025, 10:48 pm • 4 0 • view
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🌘Witch Wei (🌗 ??? 🌕) @witchwei.bsky.social

📌

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mona 🧿 @hamzam.medsky.social

📌

may 29, 2025, 10:38 am • 1 0 • view
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Cancan12312 @cancan12312.bsky.social

📌

may 28, 2025, 10:45 pm • 1 0 • view
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GoodGreatOkay-ish 🫛 @goodgreatokayish.bsky.social

📌

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chekov's engine light @catfort.fightins.online

📌

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Kari Raymer Bishop 🇨🇦 @kariraymerbishop.bsky.social

📌

may 29, 2025, 11:26 am • 0 0 • view
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nettel.bsky.social @nettel.bsky.social

📌proper usage Covid rapid antigen test

may 29, 2025, 1:30 pm • 1 0 • view
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Katea ☮ ✍🌏🌊🐈 😷🇺🇦 @katea77.bsky.social

📌 Covid testing instructions

may 29, 2025, 12:06 am • 3 0 • view
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Concentration Camp Barbie 🌮 @ljohn44.bsky.social

📌

may 29, 2025, 2:14 am • 1 0 • view
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IamFleece @iamfleece.bsky.social

📌

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Susan Kiddie 🍉 @susankiddie.bsky.social

@skyview.social thread svp

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Susan Kiddie 🍉 @susankiddie.bsky.social

📌

may 29, 2025, 1:06 am • 1 0 • view
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David Sainez @davidsainez.com

@unroll.skywriter.blue

may 29, 2025, 8:21 am • 0 0 • view
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Thread Reader by Skywriter @unroll.skywriter.blue

The thread as a shareable webpage: https://skywriter.blue/pages/did:plc:xz3qwoxwcmdfcyd6utmyeguv/post/3lqbboyfm2k2o. Powered by @skywriter.blue

may 29, 2025, 8:22 am • 1 0 • view
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Gouda Sofia @updrafter.bsky.social

📌

may 28, 2025, 10:54 pm • 1 0 • view
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Breen's Writing 🇵🇸 @breensims.bsky.social

📌

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📌

may 29, 2025, 3:57 pm • 1 0 • view
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Tarabell 💞😷💉🧑‍🧑‍🧒‍🧒🐾☮️🌈🌅 @tara4711.bsky.social

📌 RAT test (Covid test) instructions

may 29, 2025, 12:33 pm • 0 0 • view
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Michelle Ziemba @michelleziemba.bsky.social

Thanks Sean, I had all of my Covid info saved in the other place so I appreciate you resharing this again. Thank you!

may 28, 2025, 11:58 pm • 7 0 • view
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Scott @scottacanada.bsky.social

📌

may 29, 2025, 12:42 am • 2 0 • view
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Nature lover 🇨🇦🇺🇦 @bluetimes.bsky.social

📌

may 28, 2025, 11:47 pm • 1 0 • view
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Minka Duchati 🍁🌻🪻 @pwndbycats78.bsky.social

📌 covid testing detection

may 29, 2025, 9:26 pm • 0 0 • view
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Emily Limey Bell @flippyme.bsky.social

📌

may 29, 2025, 9:41 am • 2 0 • view
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📌

may 29, 2025, 4:47 am • 3 0 • view
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Mrs d’Arcy 😷💉🇵🇬🇮🇳🦘 @muggly.bsky.social

unroll @skyview.social

jul 2, 2025, 3:34 pm • 0 0 • view
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Brooke Chang 🇨🇦 @brookechang.com

📌

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DCapTO @dcapto.bsky.social

📌

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📌

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