Wikipedia:Reference desk/Archives/Science/2020 December 31

= December 31 =

Multi-shot vaccines
It's in the news that the first few Covid vaccines require two shots a few weeks apart, but there are some other multi-shot vaccines, including shingles (2 doses), rabies (3 or more doses), etc. Apparently the Pfizer Covid vaccine is two shots of the same drug, taken a few weeks apart (for some reason that hadn't occurred to me: I thought it would be drug A and then later drug B, like two-part epoxy). My questions: My reason for asking the last question is there are N doses of Pfizer vaccine available at a given time, and current policy has been to vaccinate N/2 people with their first shot, then save the remaining doses to give the second shot to the same N/2 people on schedule. But now they are talking about switching to a policy of delivering the first shot as fast as they can (i.e. use the N doses for N people) and do the second shot as more vaccine becomes available. Since there will undoubtedly be slips and delays in some places, lots of people will get the second shot later than expected, or not at all. So I'm wondering the likely public health consequence of this. 2601:648:8202:96B0:0:0:0:313A (talk) 01:33, 31 December 2020 (UTC)
 * In these multi-dose vaccines, are the doses always of the same drug?
 * Are there many other common vaccinations where more than 1 shot is involved?
 * What happens if you get the prescribed number of doses, but for whatever reason the time between doses is longer than recommended? This is particularly with regard to Covid, so since the RCT didn't address this question, any sort of reasonably science-based info is welcome (nobody should take it as medical advice, they should always follow the protocol as closely as they can, but it won't be entirely within anyone's control, so I'm asking what's likely to happen if something goes wrong).
 * Following the approval in the UK of the Oxford/Astra Zeneca vaccine, there has been considerable debate about such timing issues. discusses this and the present UK government's conclusion that it is better to give the N doses to N people (rather than N/2) when the initial supply is limited, mainly because that gives at least some protection and there is a fairly wide time window for the second dose. Mike Turnbull (talk) 13:09, 31 December 2020 (UTC)
 * The official UK line is that "For both vaccines [Pfizer and Oxford/Astra], data provided to MHRA demonstrate that while efficacy is optimised when a second dose is administered, both offer considerable protection after a single dose, at least in the short term... The Joint Committee on Vaccination and Immunisation (JCVI) has subsequently recommended that as many people on the JCVI priority list as possible should sequentially be offered a first vaccine dose as the initial priority". Professor Chris Whitty, the Chief Medical Officer for England, recently quoted a figure of "at least 70% protection" from an initial dose.   Alansplodge (talk) 14:40, 1 January 2021 (UTC)


 * Administering two shots is common for the MMRV vaccine and a recombinant zoster vaccine, and routine for several others, such as the hepatitis A vaccine. For mRNA vaccines such as those developed to offer protection against COVID-19, the mRNA coaxes the recipients' cells into producing antigens. If the antigens of two different vaccines are sufficiently similar, which means that the antibodies developed by the recipients' immune systems cross-react to the other antigen, it would seem quite likely that using these different vaccines for the two shots still offers enhanced protection. The proof should be given by clinical trials, which have not been conducted. If the second shot is delayed for too long, it will quite possibly not offer as much enhanced protection as when it is given timely. Again, clinical trials would be needed to determine the impact for these specific vaccines, but have also not been conducted. --Lambiam 13:20, 31 December 2020 (UTC)
 * Gam-COVID-Vac requires two different drugs for its two doses. Ruslik_ Zero 12:18, 1 January 2021 (UTC)

Need assistance identifying these satellite images on the covers of three editions of Oxford Atlas of the World
The Atlas of the World published by Oxford University Press has been updated with new edition released annually for more than twenty years. All the recent ones each has a satellite image as its cover. I was able to identify the sources for most of those images with ease using TinEye but there are three that I have not been able to including:
 * 16th edition
 * 18th edition
 * 24th edition

I would like to know what those satellite images are from or if not, at least what geographical location each is depicting. StellarHalo (talk) 11:58, 31 December 2020 (UTC)


 * Why not write to the OUP and ask them? --174.95.161.129 (talk) 04:34, 1 January 2021 (UTC)


 * Well, I could but they would probably say something along the line of "the information you request is in those books. you can purchase them online in here and here". Also, the main reason I am asking here is because gaining direct access to those books fore free is currently tedious due to the pandemic lockdowns. StellarHalo (talk) 06:22, 1 January 2021 (UTC)
 * You won't know until you try. ←Baseball Bugs What's up, Doc? carrots→ 16:47, 1 January 2021 (UTC)

The 16th edition could be looking east across the Horn of Africa? (just south of the tip - see this) PaleCloudedWhite (talk) 19:56, 1 January 2021 (UTC)