As the Omicron outbreak is gaining momentum, the Government has further shortened the period between the second Covid-19 vaccine dose and the booster jab from four to three months (93 days). Just in December, the timeframe had changed from six to four months.
Northland-based medical professional Dr Clair Mills explains how this change affects the body's immune response to Covid. The Hauora lead for Te Kahu O Taonui, the iwi collectively for Tai Tokerau, is working closely with Māori health providers to support their vaccine campaign.
Mills has just returned from France where she worked as the medical director for Médecins Sans Frontières (Doctors Without Borders), the biggest medical humanitarian organisation globally.
MSF provides medical aid for populations in crisis and Mills was critically involved in setting up support units for people with severe Covid illness everywhere from Afghanistan and Malawi to Yemen. Before her role with MSF, Mills was the Northland District Health Board's medical officer of health.
Q: It's been talked about many times before but could you please repeat, why do we need a booster?
A: When you get a vaccination, your body produces antibodies in response. That prepares you to be exposed to an infection. But the antibody levels start to tail off after a few months. Even though there are different mechanisms for you to respond when you see a Covid virus again, we know that having a booster vaccine is one of the most effective ways of doing that. It's basically giving your body a reminder that it needs to produce antibodies when it sees something that looks like a Covid virus.
Q: Why the change of time between the second and third dose?
A: The reason for bringing it forward a month is because we're faced with Omicron right now and we know that the infection spreads quickly. The more people that we can boost efficiently with a shorter period when their antibodies aren't low, the more protected we'll be as a community.
Like many other countries – most of Europe and some of the US – the Ministry of Health, with the technical advice of their vaccine specialists, have decided to offer it to people a month earlier. That is important in terms of equity because we know in Tai Tokerau Māori got vaccinated later than the non-Māori and are still lagging behind. That means across New Zealand an additional 100,000 Māori will be eligible for a booster now.
Q: Why did Māori get vaccinated later than the rest of the population?
A: When you look at the population curve of Pākehā and Māori – particular in Northland – our Pākehā population has quite an elderly bulge. Of course, the initial rollout was based on age so that meant more Pākehā got vaccinated earlier than Māori. In addition, all the barriers to access vaccination, that we know from previous campaigns and research, weren't addressed until quite recently.
Q: Does the change to three months impact the effectiveness of the booster?
A: If you were looking at the antibodies on a graph, you have a peak fairly soon after you've got vaccinated and then they slowly drop down until they are quite hard to detect. It doesn't mean they have gone away completely because there are other mechanisms in your immune system that will remind your body to produce antibodies. But instead of waiting until you've got low levels of antibodies where it might take you longer to produce a response against Covid, they are actually getting boosted.
Q: If I end up with Covid, what's the difference between two and three doses?
A: What we know is that Omicron has mutations which are less visible to your immune system. The booster means your body gets on to it quickly and will respond faster. The idea is that with a more recent booster your body is already being stimulated to produce a response to Covid so therefore when Omicron presents, you'll have a more effective response.
You'll be less likely to have a severe infection or to end up in hospital. I got vaccinated in France and I'm still getting all the French data that people who are vaccinated with a booster have very low risk of hospitalisation and hardly any admissions to the ICUs.
Whereas people who had no vaccines obviously had a much higher risk of hospitalisations. People who had vaccines and had their second dose in August or September last year have a middle risk, between the boosted and the unvaccinated ones.
Q: What's your message to Northlanders?
A: We've got a window of a couple of weeks to get as many people bolstered as possible because the infection will spread pretty fast and so I urge people to get bolstered while they can. Otherwise, you're going to get boosted with the real thing, unfortunately. This risk, if that happens, is that you're much more likely to end up in hospital.
For me, it's the urgency now. We don't have a lot of time before we get a big wave of Omicron. It's important that whānau get out and get their boosters, and if possible, get their children vaccinated as well.
We have the capacity if we want to share our resources around with Māori providers. We have to ensure we engage with our whānau and communities and make sure they feel ok to come in. So that people aren't coming because they owe something to their GP for example or they've had a bad experience with their GP and they don't want to come in.