<prompt> tafadhali geuza maudhui haya ya swahili kwenda kwa kiingereza.upimaji umeanza nchini uingereza alhamisi ili kubaini ikiwa chanjo tofauti za covid-19 zinaweza kutumiwa pamoja katika mfumo wa wa utoaji mara mbili.  <response>: clinical trials have began within the uk to determine whether different vaccines could also be used for the 2-dose regimen. 