The global race to produce coronavirus vaccines, in particular the development of messenger RNA or mRNA technology, has given hope to researchers who have struggled for years to produce shots that could save millions of lives.
Vaccines take several forms, with some made from bacterial or viral particles treated to prevent virulence, while others consist of inactivated or weaker virus particles.
Yet more are made from components of the pathogen or, like the Oxford-AstraZeneca Covid-19 vaccine, consist of viral vectors that deliver genetic material into the cells of recipients.
Two of the earliest-approved and most effective vaccines against coronavirus, from Pfizer-BioNTech and Moderna, are based on mRNA technology.
Work continues to develop Covid-19 vaccines effective against new coronavirus variants.
And some researchers are eyeing an even more ambitious goal: to create broad-spectrum vaccines protective against new types of virus - even before they emerge.
Researchers have warned, however, that there are significant technical hurdles to overcome before such “pan-virus” or “pan-coronavirus” vaccines could be released.
Here s what we know so far:
Why do we need a better vaccine?
Events in recent decades – and not just the latest pandemic – have highlighted the possible need for such widely applicable jabs.
In 2002, a novel coronavirus sparked the Severe Acute Respiratory Syndrome (Sars) epidemic, while the coronavirus responsible for Middle East Respiratory Syndrome (Mers) was first identified in 2012.
New variations of the virus are plunging already reeling countries into fresh lockdowns
Nurses talk in front of the 28 de Agosto Hospital in Manaus, Amazon State, Brazil. AFP
A healthcare worker uses a pipette to process Covid-19 test samples at the SpiceHealth Genome Sequencing Laboratory set up at the Indira Gandhi International Airport in New Delhi, India. Bloomberg
A health worker prepares an injection with a dose of the Pfizer-BioNTech Covid-19 vaccine at the Hospital Infantil in Ciudad Juarez, Mexico. Reuters
An undertaker sprays disinfectant liquid around the grave of a person that passed away due to Covid-19 at Glen Forest cemetery in Harare. AFP
What to expect from the next generation of Covid-19 vaccines
Dozens of coronavirus jabs under development aim to be cheaper, easier to distribute and effective against different strains
Dr Nawal Al Kaabi, chair of the National Covid-19 Clinical Management Committee and Dr Walid Zaher, vaccine project leader at G42 Healthcare, pictured in Abu Dhabi. Their teams will lead a plan to produce the Sinopharm vaccine in the UAE this year. Victor Besa / The National
Dr Al Kaabi, pictured with Ashish Koshy, chief executive of Sinopharm vaccine trial partner G42 Healthcare, said the country aims to inoculate 70 per cent of the population to achieve herd immunity. Victor Besa / The National