By Helen Petousis Harris 28/07/2016 1


Today PHARMAC announced their changes to funded vaccines. Basically they did what PHARMAC do, and within their given budget they negotiated the best deal they could with the suppliers to prevent as much disease as possible. After all, that is what we want them to do on our behalf. So who wins and who loses?

The reality is, that like most of us, there is a budget and we can’t have everything we want. However, the other reality is that PHARMAC are pretty good at cracking deals and they encourage competition between pharmaceutical companies. While commercial matters are waaaay outside my expertise there are winners and losers in this year’s vaccine deal. On the winning team commercially have been GSK, who have secured the contract to supply most infant and childhood vaccines; and Sequris (previously CSL), who now have a generously expanded HPV programme to keep them busy.

Unfortunately Pfizer and Merck have lucked out this time, with Pfizer losing the pneumococcal vaccine (Prevenar13) contract for the schedule and Merck who have taken a hit by losing the MMR and Rotavirus vaccine contracts. Hasta la vista, but I’ll be back. Because next time around it is all up for grabs again.

But the real winners here are the NZ public. I am not seeing much of a downside for the people, it seems all gain to me. My predictions:

  • Over the next few years we are going to wipe out the bulk of the 55,000 cases of chicken-pox we have every year and almost all the 450 hospitalisations – like many other civilised countries already have.
  • Over the next few years we are going to almost eradicate genital warts, like Australia have. We are going to see early signs of a reduction in oropharyngeal, penile, anal cancers and a bigger impact on cervical, cancers

With one caveat – we need to achieve and maintain high coverage of these vaccines.

New pneumococcal vaccine

Another change is the brand of pneumococcal vaccine. Since NZ introduced a pneumococcal vaccine (Prevenar7) to the programme the very nasty Invasive Pneumococcal Disease has been virtually obliterated. It is a beautiful thing. Here is a graph from the ESR 2014 Surveillance Report.

Decline in Invasive Pneumococcal Disease in NZ children under two years following PHARMAC funding of vaccine

Decline in Invasive Pneumococcal Disease in NZ children under two years

So what about going from a pneumococcal vaccine with thirteen types back to the one we had before with only ten types in?

This move is more complicated to explain. The Prevenar13 vaccine has thirteen serotypes in (PCV13) and the Synflorix vaccine has ten serotypes in (PCV10). Yes thirteen is generally better than ten when it comes to vaccines.

The three additional serotypes are called 3, 6A and 19A. In 2014 there were 7 cases of type 3 and 12 cases of type 19A in children eligible for vaccination (under two), so theoretically these are cases that were directly preventable by PCV13. But to complicate matters the PCV10 has been shown to offer moderate cross protection against 19A. It has demonstrated protection against about 60-80% (wide CIs) of 19A based on studies from Brazil and Canada. [Here for commentary in Lancet]

NZ has chopped and changed the pneumococcal vaccine. In 2008 it was PCV7, in 2011 it changed to PCV10, then in 2014 it changed to PCV13. Today, PCV10 and PCV13 are the competitors in the market.

19A

 

In 2015 when the cases dropped, most infants and children had received PCV10, it was almost December 2014 before PCV13 was the brand going into most arms (and little legs). You can see it is fickle and if you look back over many years it dances around going up and down.

You can also see there are very few cases. Each of these cases is a child in hospital. Don’t get me wrong, every case is a case too many. Fortunately no infant under two died in 2014. Also, anyone who has an underlying condition that puts them at high risk from this disease still receives the PCV13 vaccine.

However, the reality is, the difference in hospitalisations we would expect to see as a result of using PCV13 over PCV10 are likely to be in the order of one or two or three, hard to say. If you balance this against the number of hospitalisations (and deaths) that will be prevented by the introduction of chicken-pox vaccine and the explosion of the HPV programme, presumably as a result of the savings made by cracking a deal with GSK, then from a public health and PHARMAC perspective it is a no-brainer. These are the decisions that have to be made, I am very glad it is not me that has to make them.

From the NZ data to 2015 there does not seem to be evidence that the decline in 19A observed in 2015 can be attributed as a direct result of the use of PCV13 (maybe it is but there is no scientific evidence either way right now). This is because, as of 2015, too few children in the under-five age group had received any doses of PCV13 over the observation period and there were most certainly too few individuals vaccinated with PCV13 for any herd immunity to occur.

Given the fluctuating pattern of 19A, and the very low numbers of cases available for observation it does not seem appropriate to draw conclusions about the performance of either PCV10 or PCV13 on serotype 19A in NZ. Time and further research will tell.

That is my take on it anyway!

 

Featured image: Wikimedia / Jan Christian


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