Plans by the government to begin offering Covid-19 booster vaccines to vulnerable and at-risk populations are being viewed as a step in the right direction towards the fight against the scourge.
For a long time, the focus for the Ministry of Health has been on ensuring that as many people as possible get initial doses of available doses.
But based on emerging data with regard to the waning efficacy of the vaccines (a few months after the jabs are given) health experts are now recommending booster doses to address this challenge.
The additional jabs are also going a long way in helping countries deal with the seemingly endless mutations of the virus that causes the disease (SARS-CoV-2), such as the current Omicron, which are highly infectious.
As per the recommendations of the Health ministry, priority for these booster doses will be given to vulnerable and at-risk populations - such as the elderly and individuals with pre-existing conditions.
This decision is timely, as findings from new studies indicate a gradual reduction in the effectiveness of the Oxford-AstraZeneca vaccine, which was widely given to vulnera-ble populations throughout this year.
For many months, it was the only jab available for public use, before the government received sufficient doses of this particular vaccine as well as many other varieties, which enabled it to make the jabs available to the wider population.
A new study published in the Lancet Journal indicates that protection offered by the Oxford-Astra Zeneca Covid-19 vaccine declines three months after receiving the re-quired two doses.
The findings of the research, informed by data from Brazil and Scotland, suggest that booster programmes are, therefore, needed to help maintain protection from severe disease in those that have received the initial doses of the jab.
During the research period, scientists from both countries analysed statistics for two million people in Scotland and 42 million individuals in Brazil who had been vaccinat-ed with the Oxford-Astra Zeneca vaccine.
Researchers also estimated vaccine effectiveness by comparing outcomes of people who have been immunised against with those who were unvaccinated.
In the end, the findings of the study showed that there was approximately a five-fold increase in the chance of being hospitalised or dying from Covid-19 in Scotland, near-ly five months after being double vaccinated (compared with two weeks after receiving a second dose of the Astra Zeneca jab).
The study further revealed that the decline in effectiveness begins to first appear at around three months and increases threefold, just short of four months, after the sec-ond vaccine dose. Similar numbers were seen for Brazil.
“Vaccines have been a key tool in fighting the pandemic. However, their waning effec-tiveness has been a concern for a while. By identifying when waning first starts to oc-cur in the Oxford-Astra Zeneca vaccine, it should be possible for governments to de-sign booster programmes that can ensure maximum protection is maintained,” stated Professor Aziz Sheikh, the lead author of the study and Director of the University of Edinburgh’s Usher Institute, based in Scotland.
“If eligible for a booster and you have not had yet had one, I would highly recommend that you book one soon,” he said.
Professor Vittal Katikireddi, another author of the study from the University of Glasgow said: “Our analyses of national datasets from both Scotland and Brazil suggest that there is considerable waning of effectiveness for the Oxford AstraZeneca vaccine, with protection against severe Covid-19 falling over time.
This highlights the importance of getting boosters, even if you’ve had two doses of the vaccine, as soon as you are able to.”
The study was funded by the UK Medical Research Council, UK Research and Inno-vation Industrial Strategy Challenge Fund, the National Institute for Health Research and Health Data Research UK (HDR UK), as well as the Scottish Government.
“This research is a great example of what can be achieved through global collabora-tion when it comes to the use of data for health research.
By drawing on findings from data sets in two countries with differing dominant Covid-19 variants, Delta in Scotland and Gamma in Brazil, the researchers have been able to disentangle vaccine waning from the effects of changes in variants.
This has strengthened the evidence for ongoing booster programmes,” noted Prof Andrew Morris, the Director of Health Data Re-search UK.