Science – Vaccines to the rescue

While New Zealand is among a small group of countries doing well in responding to the Covid-19 pandemic, the broader world situation is dire. It’s not surprising, then, that the announcement that the initial Pfizer-BioNTech vaccine is 95 per cent effective in suppressing Covid-19 symptoms has generated a global sigh of relief.

However, even if a vaccine is able to confer individual protection from Covid-19, it may not reduce transmission to the same extent, and the Pfizer vaccine has some other limitations, including the need to be stored at very low temperatures, which will make its transport to poorer regions problematic. For any of the candidate vaccines, about 25 to 50 per cent of the population would need to become immune to achieve suppression of community transmission.

The massive scale of doses required is offset by the large number of vaccine development projects – at present, 54 in human clinical trials and more than 87 in pre-clinical testing. The Pfizer vaccine project alone will produce 1.3 billion doses by the end of 2021. The Oxford AstraZeneca vaccine now seems likely to become available by the end of 2020. The UK Government has ordered 100 million doses, which is enough for the entire country. The most recent Moderna vaccine is 94.5 per cent effective and looks likely to save lives among  groups of people – those over 65 and various ethnicities – impacted most by Covid-19.

The science strategies of these vaccine projects generally fall into two broad categories: Genetic vaccines – these deliver the coronavirus’ own genes into our cells (such as the Pfizer and Moderna vaccines) and viral vector vaccines – engineered to carry coronavirus genes (the Oxford vaccine). This science diversity is useful as it generates a range of candidate vaccines, with each vaccine having particular advantages for different age cohorts. The deployment of the vaccines will then involve ethical issues around priority of access. Priority access is expected to be given firstly to frontline health staff and aged-care facility residents and then to the other vulnerable cohorts within populations.

The most important reassurance for the community is that all of the approved vaccines that become available will be very safe for recipients. That reassurance is based on the clinical trials involving many thousands of human volunteers (43,000 in the Pfizer trials), who will receive the vaccines before each vaccine is deployed more generally. Finally, the approval of the results of these clinical trials by leading regulatory organisations, such as the US Food and Drug Administration, will further ensure public safety.

When thinking of the global recession associated with the pandemic, it should be noted that the leading trading partners of New Zealand are China, Australia and the US. China is emerging from the pandemic with significant growth, Australia’s recovery is comparable to that of New Zealand and the US is still deeply in the throes of the pandemic. Therefore, the timely new Asia-Pacific trading bloc, the Regional Comprehensive Economic Partnership, including NZ, China and Australia, bodes well for future economic recovery from the pandemic.

Emeritus Professor Ralph Cooney
r.cooney@auckland.ac.nz