J&J vaccines not expiring soon & Sisonke study not open to general public, says Prof Gray Search Polity Note: Search is limited to the most recent 250 articles. To access earlier articles, click Advanced Search and set an earlier date range. To search for a term containing the '&' symbol, click Advanced Search and use the 'search headings' and/or 'in first paragraph' options. With... Clear Search Sponsored by Sponsored by The Sisonke Johnson & Johnson trial has denied that the implementation study has been expanded to cover the general public in order to save vaccines from expiring. The study, which started in February, aims to vaccinate 500 000 healthcare workers against Covid-19 and is expected to end this weekend.