Following criticism, the UK has announced changes in its travel and quarantine rules and said that it now recognises Covishield as a vaccine. However, fully-vaccinated Indians still have to quarantine because of "vaccination certification issues", the UK government has said. Medanta Group MD Dr Naresh Trehan said there is enough data to show the CoWIN app in India very robust and there is no reason anyone in the world should doubt it. He also said there was no point in retaliating at the UK for taking such steps and instead more data should be provided to them to clarify their doubts.