Science – Covid-19: Your urgent questions answered

According to a recent poll, two thirds of Kiwis believe that the best way out of Covid-19 is the continuing pursuit of the 90 per cent vaccination level. With an 80 per cent vaccination level already exceeded in the Auckland region, there seems little doubt now that we will exceed 90 per cent soon. Recent modelling reveals that lifting the level from 80 per cent to 90 per cent makes a dramatic difference to various critical outcomes: Infections reduced from 861,391 to 13,398, hospitalisations from 43,757 to 476, deaths from 4,936 to 50 and peak beds occupied from 3319 to 20. So, what are the 10 most common remaining questions among communities who have not yet accepted vaccinations?

1. What is the difference with Pfizer vaccine effectiveness between one jab and two?
   The first jab efficacy is 60 per cent, and after the second jab the efficacy is 95 per cent.
2. Will we need a booster vaccination within a year?
   In the future, booster vaccination may be necessary to maintain antibody levels. This is not unusual given that vaccination against common influenza virus is required annually.
3. Will new delivery technologies other than injections be offered soon?
   Nasal technologies are being developed but are not yet approved. These will have the advantage over injections that they do not require the dedicated service of health professionals. Nasal delivery of vaccines acts as a “first entry block”. This means they block the pathogen entry, while inducing local microbial-specific immune responses, thus increasing the general efficacy of the vaccine.
4. Globally, how many people have had at least one vaccine jab so far?
   More than six billion doses (33% of the global population) have been given so far and serious side effects are rare.
5. What is the global death rate for Covid-19?
   According to a recent analysis by The Economist, the number of Covid-19 related deaths is about 20 million. With the low vaccination rates among poorer countries, this figure is expected to continue to rise.
6. How much more contagious is the Covid-19 Delta variant than influenza?
   Relative contagiousness is measured by the reproductive number, R0, which is 2 for influenza and about 8 for the Delta variant (latest updated USA CDC R0). In two stages of social contact, a single unvaccinated person could infect 64 (8×8) others with the Delta virus. The comparable number of transmitted influenza infections is 4 (2×2).
7. Why not open up New Zealand right now like the UK?
   The UK has in many ways been one of the least successful wealthy countries in managing Covid-19. Deaths pro rata: UK, 2000 per million; New Zealand, five deaths per million.
8. Of those who are hospitalised with Covid-19, how many have been vaccinated?
   According to a recent USA survey, between 99.9 per cent and 95 per cent of Covid-19 hospital patients were unvaccinated.
9. Does vaccination reduce transmission of Covid-19 between people?
   Vaccinated individuals are 80 per cent less likely to spread the virus to unvaccinated household members.
10. What countries have successful vaccination certificate or passport systems in place?
    Israel, EU and France have all successfully deployed vaccination passports and health passes using QR codes. These typically enable international travel and are required for access to restaurants, bars and major events. NZ is expected to launch a vaccination passport within a month.