Support #2076
openIssues with xx_hadcvvac variables in COVID-19 data collection
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Description
Good evening,
I am currently analysing data from the xx_indresp_w datasets of the COVID-19 data collection, specifically from wave 9 (ci), wave 8 (ch) and wave 7 (cg). From the documentation, the questions xx_hadcvvac (about having received the COVID-19 vaccine in each survey wave) should be asked to respondents that have not already answered that they received 1 or 2 doses of vaccines in previous months (answer codes 1 and 2). However, by cross-tabulating the answers to the xx_hadcvvac questions for wave 7 and 9 for respondents present in wave 9 and 7 (left-joining the datasets by respondent ID pidp, i.e. matching all respondents in wave 9 with those that were also in wave 7):
table(ci_hadcvvac = wave_9$ci_hadcvvac, cg_hadcvvac = wave_9$cg_hadcvvac)
with wave_9 the left-joined dataset, I obtain the following table:
cg_hadcvvac
ci_hadcvvac   -9   -8   -2    1    2    3    4
         -8    0   10    0  133    9  492 4835
         -2    2    0    2    0    0    0    4
         1     0    0    0    4    1    1  133
         2     0    3    1 1663  116   36 2538
         3     0    0    0    0    0    1    5
         4     0    0    0    2    0    3  322
	As you can see from the numbers in bold (took as examples), there are some respondents vaccinated in wave 7 that appear to be asked the question again in wave 9. Am I missing some information?
Thank you very much in advance for the support.
Best regards, 
Laura