As
@SpokeyDokey said "thin". Reuters is reporting facts. And your description of 'causing some concern' is bang on, but maybe better put "causing some concern in Germany". There are no results in Germany sfaik.
It quotes 'German Media', specifically the daily papers: Handelsblatt and Bild, who appear to have selected a small section of the trial report data to allow this story to 'run' and link it with the European (et al?) vaccine supply 'crisis'. The EMA meet on 29 Jan to consider authorising the Oxford-AZ vaccine. But I guess there's no hurry if they aren't going to receive supplies for a while (see other story). This mirrors the approach of the UK MHRA to authorising the Moderna vaccine: not getting it till March so there was no hurry.
The UK will now have data, growing by the day, on the effectiveness of the Oxford-AZ vaccine after one dose after 4+ weeks in over 80s. I think this may help alleviate any rational concerns the EMA has, OR confirm that there's an issue. This does seem to be another 'we have no evidence' approach, and in normal times that'd be the default approach. But times are not normal: these are emergency authorisations and it's likely that on balance, delay will cost more lives than prudence, waiting for the evidence.
I think it might have been reasonable for you to then include in your post that AstraZeneca had described the German media reports . . . . . as “completely incorrect”.
"In a written response, AstraZeneca described the German media reports saying its COVID-19 vaccine was shown to have a very low efficacy in the elderly as “completely incorrect”.
"It said Britain’s JCVI supported the vaccine’s use in the elderly. It also said that a strong immune responses to the vaccine had been shown in blood analysis of elderly trial participants.
"Britain on Dec. 30 became the first country to approve the two-shot vaccine and did not impose an upper age limit. It has so far focused on the elderly and healthcare workers for its immunisation campaign.
"AstraZeneca’s main trial in Britain started testing on adults no older than 55 because it initially focused on healthcare personnel and front line workers in active duty." [Comment: Because AZ knew that those trial participants (like
@winjim maybe) were more likely to be exposed to the virus and therefore the trial requirement (volume of infections in the placebo group) could be met in a shorter time frame.]