Toby Morris
Toby Morris

SocietyOctober 29, 2021

Siouxsie Wiles & Toby Morris: What difference does the vaccine make? Just look at this

Toby Morris
Toby Morris

The data on case numbers and hospitalisations in New Zealand’s delta outbreak send a resounding message to anyone who doubts why Covid vaccines matter to protect against a deadly disease. 


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So now we have community cases of Covid-19 in Christchurch. As of last night it was only two people but only time will tell how big the cluster is going to get. I hope it stays small and the test-trace-isolate strategy can stamp it out without the city needing to move up the alert levels. Unsurprisingly, the person who unwittingly took the virus to Christchurch was unvaccinated. They had been in Auckland for a short time and for a legitimate reason. At some point during their stay, they were exposed to the virus. Genomic sequencing and case investigation will hopefully help us understand where and when. While the person tested negative before travelling back home to Christchurch, it turns out they were incubating the virus. Now they’ve tested positive and, unfortunately, had contact with people while infectious. 

The data from our delta outbreak really does stand as a testament to just how effective the Pfizer vaccine is at preventing people from catching Covid-19, and if they do, from being hospitalised. Just check out these numbers. First, the cases.

As of October 25, there were 2,681 community cases in the delta outbreak. Of these 1,984 were people who were unvaccinated – a staggering 74%. About one in four were children under 12 who couldn’t be vaccinated. Partially vaccinated people made up 566 of the 2,681 cases. That category – just over 20% – includes people who had only had their first dose or a second within the last 14 days, meaning they weren’t fully immunised. As for fully vaccinated people? Just 136 cases, or 5.1%. 

It’s a similar story with hospitalisations. As of October 25, 224 people had been hospitalised in New Zealand’s delta outbreak. The overwhelming majority of them, 168 people, were over 12 and unvaccinated. That’s 75%. Partially vaccinated people were the next biggest group. There were 45 of them. That’s about 20%. Just three of the people hospitalised (1.3%) were fully vaccinated. 

Put simply, vaccines work. So, it’s fantastic that more than 85% of eligible people in New Zealand have had their first vaccine dose and more than 70% have had two. Before we get too excited, though, we need to remember that this equates to just over 70% first doses and 60% fully vaccinated when we look at the population of New Zealand at a whole. 

In other words, there are still plenty of people in our communities who aren’t yet vaccinated. A large proportion of these are children under 12. And as we’ve seen from the data, more than 540 have been infected so far during this outbreak. Eight children under 12 have been hospitalised. Hopefully it won’t be long before a vaccine will be available for our children too. The US Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee have just voted 17 to zero (with one abstention) in favour of making a Covid-19 vaccine available for five-to-11-year-olds. What they were voting on was a lower-dose version of Pfizer’s mRNA vaccine. Adults get two 30 microgram doses. Five-to-11-year-olds are going to get two 10 microgram doses. 

Unfortunately, it’s not a simple case of just diluting the adult doses to get a kid’s version. The Pfizer vaccine is made up of mRNA wrapped in little balls of fat and then bathed in sugar and salts. All those ingredients need to be in the right ratios for the vaccine to be effective. That means the kid’s vaccine is a different formulation to the adult’s version. The question now is, how will Pfizer satisfy the enormous demand there’s going to be for both formulations? I wish they would agree to transferring their technology to other companies and organisations around the world so everyone could benefit.  

While we wait, we need everyone who is eligible to be vaccinated to get vaccinated right now. That will massively reduce their chances of being a case, being hospitalised, and potentially passing the virus on to other people. Time is running out to enjoy the summer holidays catching up with friends and family.

Keep going!