KUALA LUMPUR, Sept 8 — A Covid-19 vaccination programme may require booster shots, said an immunologist who also stressed that viral mutations were unlikely to significantly affect coronavirus vaccine development.
ABC reported that research on hamsters showed a single dose of the Covid-19 vaccine candidate by the University of Queensland provided a good level of protection against the virus in the lung, while a double dose provided good protection against virus replication and the disease.
A booster shot means an extra dose of vaccine that will be given in a certain time frame to augment the immune system and antibody responses.
The Australian government has reportedly announced an agreement to purchase over 84 million doses of two potential coronavirus vaccines: the candidate by the Oxford University and AstraZeneca partnership, and another candidate from the University of Queensland and CSL. A total of 3.8 million doses of the Oxford-AstraZeneca vaccine are expected to be available for Australians in the first two months of next year.
The Oxford-AstraZeneca vaccine, touted as one of the frontrunner coronavirus vaccine candidates, reportedly produced a “robust immune response” in its first human trials. It is currently in stage 3 clinical trials.
Nobel Laureate Professor Peter Doherty reportedly cited the usage of the measles vaccine with one shot in the United States in 1968, but outbreaks were identified again in 1981 in the country.
“It turned out that children maintained their immunity while there was still enough measles virus circulating in the community to give them a mild reinfection,” he was quoted as writing.
“Once transmission fell off, though, the clinical disease returned.”
He also stated that a second shot of the vaccine finally solved the issue, saying: “No matter how successful any vaccine may be, this is what we could well be looking at with Covid-19.”
At the same time, researchers also noted the chances of merging more than one vaccine, identified as “prime boosting”.
Professor Paul Young, head of chemistry and molecular sciences at the University of Queensland, reportedly stated that the “prime boosting” strategy has been around for almost 20 years, but it has not been tested on human beings.
“But we know in animal studies it works,” he was quoted saying. “You prime with one particular vaccine type, and boost with another.”
“For example, the Oxford vaccine — based on a viral vector — and the UQ vaccine are both targeting the same protein, but it’s delivered in slightly different ways.”
He also stated that the prime boosting method can be beneficial as it helps to focus precisely on the immune system.
However, he also stressed that mutation of the SARS-CoV-2 virus will not be a hurdle for the vaccine invention process.
“Whilst there are mutations accumulating as this spreads throughout our population … it’s not at a significant rate such that a vaccine is likely not to work against them,” he added.