# How immune am I? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** factual, covid-quarantine\ **Created:** [April 9, 2021, 5:07pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691 "2021-04-09T17:07:13Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 9, 2021, 5:07pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/1 "2021-04-09T17:07:13Z")
So basic immunology question here: I got my first shot of Pfizer on Monday, so let’s say 96 hours ago. For simplicity, let’s ignore the 21-day second shot, and define 100% immunity as being the most immune I’m going to be, which I understand takes 14 days. What does the immunity curve look like? What % immune am I now, 96 hours in? I wouldn’t be surprised if the data didn’t exist for SARS-COV-2 yet, but if there’s data that answers that for other viruses, I’d love to hear that! And don’t worry, I’m not going to go do anything crazy based on this data. I’m still in semi-quarantine, wearing my mask when I go out, etc, etc, and will continue to do so. I’m just curious. ---
**Author:** ![FigNorton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fignorton/32/5619_2.png) [@FigNorton](https://boards.straightdope.com/u/FigNorton)\ **Post date:** [April 9, 2021, 5:18pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/2 "2021-04-09T17:18:14Z")
Basically zero protection. It doesn’t kick in for about 8 days at all and the 80-90% efficacy comes at some point 2 weeks+. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 9, 2021, 5:19pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/3 "2021-04-09T17:19:34Z")
Is that specific to SARS-COV-2, or generally true of viruses, or true of some classes of viruses, or what? ---
**Author:** ![FigNorton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fignorton/32/5619_2.png) [@FigNorton](https://boards.straightdope.com/u/FigNorton)\ **Post date:** [April 9, 2021, 5:22pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/4 "2021-04-09T17:22:10Z")
It’s specific to the Pfizer vaccine and this virus. There is no “generally viruses/vaccines work like this”. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 9, 2021, 5:23pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/5 "2021-04-09T17:23:22Z")
> [@FigNorton](#): > > It’s specific to the Pfizer vaccine and this virus. Oh, cool. Can you cite your source on that? I’d love to read more. ---
**Author:** ![FigNorton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fignorton/32/5619_2.png) [@FigNorton](https://boards.straightdope.com/u/FigNorton)\ **Post date:** [April 9, 2021, 5:24pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/6 "2021-04-09T17:24:54Z")
Look up “Pfizer immunity Israel one dose”. This is coming from tests in the field not general knowledge of viruses. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 9, 2021, 5:28pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/7 "2021-04-09T17:28:46Z")
Thanks, but I’m not seeing what you’re seeing on a cursory glance through those search results. Seems to mostly pertain to the necessity of the second dose. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [April 9, 2021, 6:17pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/8 "2021-04-09T18:17:43Z")
fyi, I tagged this thread “factual”, indicating it is a general question type of thread. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [April 9, 2021, 6:41pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/9 "2021-04-09T18:41:53Z")
> **[Israeli HMOs: Pfizer vaccine immunity best after 14 days - ISRAEL21c](https://www.israel21c.org/israeli-hmos-pfizer-vaccine-immunity-best-after-14-days/)** > > Study of 800,000 Covid test takers, half inoculated with the first dose and half not, shows no difference in infection rate until two weeks later. This article reports on the results of a few different studies, including Pfizer’s preliminary data and real world data from Israeli HMOs. an HMO found no decrease in the odds of developing covid from 5-12 days after the first shot, but found a 33% decrease 14 days after the first shot. Another study found a 60% decrease in risk after 14 days. A small study where they actually drew blood and looked at antibody levels found that after a week, only 1% of people had enough antibodies to matter, but after 14 days, 50% did. (Which sort of demonstrates that it may not be that YOU are x% less likely to be infected, but that the odds are y% that you will be z% less at risk…) The NEJM published a very nice study based on Israeli experience, with a lot of people and carefully matched controls. It didn’t analyze the data prior to 14 days, because they didn’t expect meaningful results. But they did publish some nice graphs. [https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2101765/20210301/images/img\_xlarge/nejmoa2101765\_f2.jpeg](https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2101765/20210301/images/img_xlarge/nejmoa2101765_f2.jpeg) Here’s the link to the whole article. [https://www.nejm.org/doi/full/10.1056/NEJMoa2101765](https://www.nejm.org/doi/full/10.1056/NEJMoa2101765) They studied the Pfizer vaccine, and the predominant variant of virus during their study was B.1.1.7 (the “UK” variant.) There was also some “original strain” running around, but not much B.1.351 (“south african”) variant. Other data suggests the Pfizer vaccine is less effective against the B.1.351 variant. ---
**Author:** ![Deeg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/deeg/32/2955_2.png) [@Deeg](https://boards.straightdope.com/u/Deeg)\ **Post date:** [April 11, 2021, 5:01am UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/10 "2021-04-11T05:01:47Z")
Thanks for the OP and the responses. I had the exact same question after getting my jab this morning with the Pfizer vaccine. Is the Moderna one similar? ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [April 11, 2021, 4:43pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/11 "2021-04-11T16:43:55Z")
The Pfizer and Moderna vaccines are very similar. I think it’s pretty much the same RNA, with a slightly different lipid vessel, and the Moderna one carries a larger dose. But Israel got early access to the Pfizer vaccine in part by agreeing to capture a ton of data. I’m not sure anyone has published any comparable data for Moderna. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 11, 2021, 7:38pm UTC](https://boards.straightdope.com/t/how-immune-am-i/939691/12 "2021-04-11T19:38:57Z")
> [@puzzlegal](#): > > an HMO found no decrease in the odds of developing covid from 5-12 days after the first shot, but found a 33% decrease 14 days after the first shot. Hey, sorry to reply so slowly here. I didn’t want you to think I was ignoring your awesome reply. I saw it on Friday, but I didn’t get a chance to read through the linked articles until today. This is exactly what I was looking for. I appreciate it!