London, Dec 17 : In order to make the global Covid-19 vaccination programme successful, the available vaccines must be able to do all three of -- prevent infection becoming established in an individual, prevent disease progression and prevent onward transmission, say researchers. "Whether all three of these goals will be met by 'first generation' vaccines is not known, but is vital to the long-term success of the programme," said the study published in the journal Anaesthesia. "Preventing onward transmission -- referred to as 'sterilising immunity' is particularly important as it is epidemic modifying," said the UK's influential Scientific Advisory Group for Emergencies (SAGE) committee. "It is possible that the first vaccines, including those being released now, maybe more effective in preventing disease progression and hospitalisation and less effective in preventing transmission," explained study senior author Jeremy Farrar from SAGE. "Knowledge of their performance in pre-approval trials and in surveillance trials after licensure will enable further modifications such that improved second and third-generation vaccines may be available later in 2021 and beyond," Farrar added. They also emphasise the importance of prioritising those most vulnerable and healthcare workers before the wider population. The authors stated, "Vaccination is a global rather than a national necessity." The World Health Organisation (WHO) ACT-accelerator and COVAX initiatives both emphasise the importance of vaccines reaching the most vulnerable and healthcare workers in all countries at a similar time. Widespread vaccination of one or a few countries without addressing this need globally is in no one's interests and will not provide the protection we all need. "No country has mounted a whole population vaccination campaign in living memory, and it will need to be undertaken with local leadership and cultural sensitivity," the experts stressed. They also discussed the implications of the widespread vaccination and the challenges for those who don't get vaccinated. They asked: "Will a certificate of vaccination (a vaccine passport) be a requirement for patients and their families before elective surgery, or to work in the health or social care, to travel abroad, or to attend medical conferences, or even to participate in the Olympics? The authors make clear the vaccine is not a panacea, and that SARS-CoV-2 will only be brought fully under control by also continuing to adapt our behaviour, plus better access to diagnostics and treatments, but add: "safe and effective vaccines will undoubtedly change the trajectory of the pandemic, rebuild confidence and start to return the world to the 'pre-COVID' era." "There is no merit or safety in creating high rates of vaccination and low rates of disease inside one country's borders if this is not replicated throughout the rest of the world. We really are all in this together," they concluded. /IANS