Pertussis notification and vaccination status in context

Across the globe it is known how important the pertussis (whooping cough) vaccine is in preventing both infection and severity of infection with Bordetella pertussis.

Along with vaccines for diphtheria and tetanus, then polio (1950’s), measles, mumps, rubella (1960’s) the Australian pertussis vaccine has contributed to an astonishing 99% reduction in deaths from vaccine preventable disease. Just after the turn of the century pertussis, diphtheria and tetanus vaccines alone had saved over 70,000 lives whilst the population had almost tripled since their inception. Since then pertussis vaccination alone has saved around another 10,000 Australian lives.

From the World Health Organisation, to national or state health authorities across developed nations to your local doctor, the evidence is compelling. Although anyone can catch pertussis it is babies under 12 months who are most vulnerable to infection. The disease can cause disability and death in the unvaccinated. Whilst immunisation provides antibodies to fight pertussis, it does not provide “magical protection”. For that you need chiropractors or other practitioners of alternatives to medicine.

Immunisation against pertussis does mean:

  • A significantly reduced chance of being infected
  • A significantly reduced severity of infection if infected
  • Protection of unvaccinated individuals that one may come into contact with
  • Low levels of community infection with high levels of immunisation

Pertussis epidemics follow on from reduction in immunisation across the community, leading to a drop in herd immunity. The present epidemic Australia is experiencing began in Byron Bay, an area with very low immunisation rates, and then spread to other areas of low immunisation. From the backyard of Meryl Dorey’s anti-vaccination lobby group the seeds for this epidemic were sown a decade ago. Brynley Hull and Peter McIntyre wrote in January 2003 [page 12]:

Although immunisation coverage has greatly improved over the past five years in NSW, and many areas have reached coverage targets, there are areas in NSW where the level of registered conscientious objection to immunisation is great enough to affect immunisation coverage, as measured by the ACIR. One such area is northern NSW, and the Byron Bay SLA in particular, where the rate of conscientious objection is one of the highest in the country.

Despite the crystal clear science and undoubted success of immunisation, movements against all vaccines have grown. They have kept pace with internet driven conspiracy theories, imaginary diseases, imaginary cures and new age beliefs. The most successful currency used by those opposed to scientific success is ignorance and misinformation.

An excellent example regarding pertussis vaccination is that many people incorrectly believe all vaccines, with the exception of influenza, provide lifelong immunity. With pertussis, vaccine induced immunity wanes over time and as noted above whilst it reduces the chance of infection, it is not an impervious shield. Antivaccination lobbyists have taken advantage of this to infer that the pertussis vaccination schedule itself has failed. First, we have ignorance – the expectation that immunity is lifelong. Then follows misinformation.

For example as debunked here more than a few times, figures describing vaccination levels and notification of infection are frequently misused by the Australian Vaccination Network to falsely refute the efficacy of immunisation. Yet these clumsy attempts are piecemeal and misleading. Time and again infection notification and vaccination status is highlighted and infused with qualities that serve to misinform. Placing figures in context yields a very different picture which, given that they seek to deny international trends that have existed for decades, is not surprising.

The question, or challenge if you will, is about the veracity of the pertussis vaccination schedule. Thus we must take care to ensure we elucidate notifications related to full immunisation as per the schedule. Take the following table of children between 0 – 4 years old, diagnosed with pertussis:

Pertussis notification by vaccination status 0-4 years, Australia August 2011

We see that a total of 9,333 notifications have been tabulated. 5,296 or 56.7% are fully vaccinated.

986 are partially vaccinated. 800 are not vaccinated. 754 are ineligible for vaccination. This gives us a total of 2,540 or 27.2% who are not fully vaccinated.

1,497 or 16% are unknown.

Do these figures reflect infection in the community? No, they reflect the vaccine status of children diagnosed.

Firstly as the table informs us “fully vaccinated” does not necessarily conform with fully vaccinated under the National Immunisation Program. Ineligible cases between 6-8 weeks of age that had received one dose in 2009 are included in “fully vaccinated”. Both these facts artificially inflate the “fully vaccinated” category.

Next we must accept that this table underestimates the actual number of infections in the community. The National Notifiable Diseases Surveillance System relies on a passive surveillance system which does not capture every case of pertussis in the community.

Which raises the question. Who is not making notification? Can we infer anything about the vaccination status of those not recorded in the above table? If so, does this help us understand the figures in the table better? As a matter of fact, yes.

Do these figures reflect the efficacy of pertussis vaccination? In other words, is this telling us that there are over twice as many infected children in our community who have been vaccinated (56.7%), than those who have not been fully vaccinated (27.2%) and thus reflect low vaccine efficacy? No.

Far more children are vaccinated against pertussis than those who are not. 95% vs 5% in fact. Even with greatly reduced chance of infection the sheer numbers of vaccinated children mean that “fully vaccinated” will dominate notifications. These figures also reflect the greater likelihood of parents who vaccinate to take their child to a GP and follow through with reporting, and also reflect the likelihood of conscientious objectors to avoid a GP and to not follow through with reporting.

For example a USA study published in Vaccine in December last year showed that parents who do not vaccinate their children are four times more likely to take their child to a chiropractor than a conventional doctor. In Australia we already know that chiropractors are vocal antivaccination proponents with strong links to antivaccination lobby groups such as the Australian Vaccination Network. Many chiropractors in Australia actively mislead consumers on the topic of vaccination making impossible claims, actively deriding vaccination.

But we can do much better than this and begin to build a profile of parents who refuse vaccination and later choose conscientious objection. Five days ago Australian Doctor reflected on the study:

A US survey found parents who refused childhood vaccinations were four times more likely to have sent their youngest, school-aged child to a chiropractor than parents of vaccinated children. Parents who conscientiously objected to school immunisation requirements were also more likely to have strong concerns about vaccines, to distrust local doctors and to have had one or more births in a non-hospital, alternative setting. […]

Are naturopathic and complementary healthcare providers reinforcing parental concerns and ‘anti-vaccine’ opinions or promoting exemptions, or are they providing healthcare without emphasizing vaccinations?

The pattern emerging is one of anti-conventional medicine, reinforced by alternatives to medicine masquerading as “complementary healthcare”.  For our purposes we must now accept that unvaccinated children may be up to four times less likely to visit a GP when ill with pertussis. This means they may be up to four times less likely to appear as a notification. Regardless of exactly how many unvaccinated children are missed, we can see with confidence that the total is skewed away from highlighting unvaccinated children.

Thus the 8.6% of unvaccinated children noted in the table above (n=800) is possibly a significant underestimation. As parents who do vaccinate are more likely to visit a GP and report diligently, the total is additionally skewed toward the fully vaccinated. What this actually means regarding community impact is best captured in this post written by a mother whose vaccinated child was infected by an unvaccinated child who had been sent to school.

Now comes the fascinating aspect. “Unknown”. What does this mean? Really? For whatever reason, somewhere along the line the child’s vaccination status is not recorded at all, is recorded and fails to make it to the final notification table or is lost to genuine confusion or poor record keeping.

However if parents are not registered on the ACIR as conscientious objectors or as completing their children’s vaccination schedules they are also listed as “unknown”. Thus the following from Brynley Hull and Peter McIntyre is compelling [bold mine]:

Additionally, the proportion of conscientious objectors on the [Australian Childhood Immunisation Register] ACIR is likely to be an underestimate of the proportion of parents who don’t immunise because they disagree with immunisation, particularly in more economically advantaged areas. There are some non-immunising parents who ‘object to registering’, and they will refuse to complete any government-provided form.

“Refuse to complete any government-provided form”. Such as those that question the immunisation status of one’s child? That also is where a significant number of “unknown” cases have their genesis.

In tandem with our emerging profile of anti-conventional medicine beliefs driving the decision to not vaccinate and combined with the observation that CO’s are likely to contribute to the “unknown” category by not registering on the ACIR, we are able to make a strong inference that unvaccinated out-rate vaccinated in this category.

Whilst it is impossible to make outright factual quantified claims and rewrite that table, we may conclude that placed in the context of community trends it gives a less than reliable indication of infected subjects within the community. What it does give us is a snap shot of the vaccine status of notifications. Placed in context those notifications appear to be skewed away from unvaccinated and toward vaccinated subjects.

The most significant reason is the overwhelming numbers of vaccinated children in the community. Although appearing as a notification they have a far less severe case of pertussis and are unlikely to suffer disability or death. Other reasons for this would appear to be the intentional avoidance or substitution of conventional medicine, diagnosis and reporting of vaccination status by those in denial of vaccine efficacy.

Of course, people will use these figures to attack the overwhelming evidence in support of vaccination. That’s just what eccentric parent Greg Beattie has tried. It’s simply gobsmacking to read his misleading claim that only 11% of pertussis infections aren’t vaccinated. Actually it’s only 8.6%.

But the point to be made is whilst only 5% of 0-4 year olds aren’t “fully vaccinated” they make up a disproportionate 27.2% of infection notifications. Unsurprisingly his novel mathematics have been dealt with unceremoniously by A Drunken Madman.

There is no debate here. Pertussis vaccination saves lives.


No vaccination is no joke

Montage of some of the more memorable moments of Meryl Dorey contradicting herself and offending common sense.

My personal request of Meryl Dorey

We (antivaccination lobbyists) are the real Australian skeptics

Meryl Dorey Jan. 4th, 2012

As many of you may have noticed, the rapidly rising pertussis epidemic in W.A. was reported by the ABC today.

This predictably sent Meryl Dorey of the AVN into histrionics. One of her ridiculous claims is that pertussis has increased “10,000%” with a 25% increase in vaccination. If you choose the figure of 332 from the very first year – 1991 – of compulsory reporting (which actually reflects sloppy reporting, gradual awareness and slow administrative changes) and compare it to today’s epidemic figure as Dorey does, it’s a dodgy trick.

A Stop the AVN member snapped this tweet on ABC News Breakfast from a cast iron flying pig

Because the “25% increase” comes from a 70% vaccination coverage in 1991 and a 95% coverage now. Strange, because a decade later in 2001, vaccination was only 70.6% and the figure of notified cases is 9,541. Sure we do have an epidemic figure for 2011 of over 36,000. But choosing a different year shows an increase of 3.8 times – not 10,000% – despite almost an identical increase in childhood vaccination.

I’ve laid it out all below. The entire method Meryl uses, and offered it back to her as actually showing a decrease of over 50% in 6 years. It’s her technique using her data sources. It’s rather silly as one cannot compare unrelated data sets. But in an attempt to draw some sense from Meryl on a fairly clear point I’ve (yet again) worked through the figures to seek a reply.

Meryl Dorey’s extraordinary claim about ABC journalistic integrity

I posted it twice today on the ABC News Breakfast Facebook page and also on Stop AVN. No “coward” stuff as Meryl alleged to Tiga Bayles. No “hiding behind anonymity” as Bayles suggested. No “suppression of free speech”. Just open and honest requests for a reply, based on evidence. Meryl’s claimed forte.

Originally I asked for a point by point response. Yet, I’m asking Meryl now, to respond to just one of my points. Just one. So far, there’s just silence. We shall see.

Summoning help, Dorey writes about: “…the rabid pro-vaxxers who would happily see all of our children dead or injured if they thought it would protect them or their families.”

Above Meryl you write:

…it’s all across Australia – why they chose WA I have no idea? (sic)

Well Meryl, whooping cough in WA has increased by almost 500% since 2009.

ABC News Breakfast

Also Meryl, WA has the lowest rate of child vaccination in the country. According to Julie Leask, senior research fellow at the National Centre for Immunisation Research & Surveillance of Vaccine Preventable Diseases, “Delay might be due to [WA’s] adolescent vax policy”.

Julie Leask Tweet

As “Australia’s leading vaccination expert” I thought you’d know these things, Meryl.

Anyway, as on Facebook here’s the same request for a reply. All I’ve updated from Facebook is the NNDSS pertussis notification figures accessed now, at time of writing, and changed it to a first person address.

As I stressed Meryl, failure to address this surely indicates admission that your claim on pertussis is false. You may very well believe it, but if so, it must stack up to scrutiny. No agro, no bullying, just a golden opportunity to speak freely. So, excuses to not answer are thin on the ground.

I hope that’s not too annoying and I’d be delighted to have you. Fire when ready….

Here’s the original from Facebook.

Hi Meryl.

Could you address this point by point please. It’s the same post as above, but I reckon it’s about time you helped clear the air. If not, do I assume you agree that your claims on pertussis are invalid?

Thanks very much:

Contrary to your claims, the epidemic began in your backyard with low vaccination rates and spread out from there. From SMH, October 2010:

“The highest rates of so-called “conscientious objectors” to immunisation are in parts of the north coast – such as Byron Bay – where 12 per cent of children born between 2001 and 2007 were never immunised for any condition. […]

An epidemic of whooping cough in 2008 and 2009 began on the north coast. It quickly swept across the state driven by low vaccination rates in some wealthy parts of Sydney. Low-income areas in western Sydney also had less immunisation and were linked to outbreaks, Dr Menzies said.”

Now, let’s debunk your claim of high vaccination rates causally equating to high pertussis infection, using – not other information and techniques – but your actual tables and own technique.

You source your 95% from under 2 year olds in a 2006 table (as per Woodford slides on your blog). Also, here it is – This makes up one half of 1/18th of all age groups from your next source, a NNDSS table of whooping cough notifications:

These are the 2 tables you sent to the NSW HCCC in September 2009 (see p. 6 to whom you made the very same claim, in response to a complaint.

You only quote absolute figures about pertussis after all – not percentages, or age groups, or if a notification is asymptomatic, or was a tourist, or international flight attendant/maritime worker/business traveller/etc.

Here’s the NNDSS age groups showing the highest infection rate is between 40 – 65 years in 2007. Before the epidemic.

Although now, the three age groups up to 14 years show large increases, if we add up the notifications above this we see that most notifications still come from adults who have no immunity. It has waned and they need a booster. Their vaccination (booster) rate is 11.3% – not 95%. We need to increase this by about 7 times to reach herd immunity.
See p. 18 of Adult Immunisation Survey to confirm 11.3%.

You are using “unrelated data”. Just like the rise in driving licences is not causally related to the rise in road trauma, or that the best safety advice (according to your thinking) would thus be to abandon licence testing. You are wrong to quote these NNDSS figures in this way, because we know nothing about their vaccine status or immunity. All we know is that most are adults who have no immunity.

So, in effect they cannot be compared – but for the record I’ll continue on as if they can be compared.

We do know pertussis fatalities occur in the unvaccinated. Vaccinated can of course catch pertussis yet experience far milder symptoms and faster recovery. The claim that vaccination for pertussis is an impervious shield has never been made by health authorities. But the claim that it should be and if not, it’s useless, is being scurrilously made by yourself.

Okay, let’s use your method on another year.

We can see (using the same NNDSS data) that 2007 was the lowest year of infection on record since 1999 – It is also the 5th lowest year since records began.
Many discount the first recording years of 1991 and 1992 as very, very low anomalies that show a slowish start to new legislation requiring reporting of whooping cough. This would make 2007 the 3rd lowest ever. But I’m happy to take the 5th lowest year ever.

Rather different to your claim, no? But from your data source no less.

Now, looking again at your vaccination rate table ( we see 2001 had only 70.6% vaccination. Infection was 9,541 Aussies. By 2007 – still using both your data tables we see 95% vaccination of babies and 4,864 cases of pertussis (

So, using your “technique” on merely another part of the same NNDSS table we can also claim vaccination more than halved pertussis notifications in a mere 6 years.

Your data, your method, the very same tables you quote from. Why then is this not your message? Why don’t you tell Aussies that these sources show a greater than 50% drop in whooping cough in just 6 years?

Because it’s selective statistical sleight of hand, is it not? We both can’t be right. It’s a simple trick – and I’m arguing that you know it is.

You are intentionally misleading Australians. This is why the NSW HCCC issued a public health warning that you “quote selectively from research to suggest that vaccination may be dangerous.”

Also, it’s strange that you cite 1990 vaccination coverage of 70% vs 2006 coverage of 95%, omitting to say it dipped to 61% in the mid 90’s and had only increased by 0.6% in the 10 years from 1991. Could this be because you want to create an impression? Perhaps.

It’s all in your table. Should you not address all figures? Why do you not address all figures?

Also, a good look at any NNDSS notification table shows rises and falls in infection. Contrary to your claim of a steady increase in infection as vaccine coverage rose, pertussis always rises and falls.

In fact the first 10 years when coverage went from 70% to 61% to 70.6% corresponds to notification levels similar to and greater than the second 10 years (

1997 is almost as high the 2008 epidemic year and vaccination coverage was under 70%. So, again we must ask – are you seeking to create an impression?

Epidemics are a different ball game. Once immunisation fell below a safe level in Byron Bay it took off like lots of little fires in low immunisation areas joining to create a massive bush fire.

So, low immunisation caused this outbreak not any problem with the vaccine. The answer? Get adults immunised and ensure babies get cocooned and immunised ASAP.

There’s nothing to stop me using the very same data and going around saying Australia had one of the lowest pertussis levels since notifications began, until your, Meryl Dorey’s lobbying against vaccination led to the 2008 epidemic (and cite Dr. Menzies, plus news reports etc to back me up).

But science doesn’t make leaps like that. We’d need better research. You really don’t use science, despite boasting of such – just tricks with scientific data hoping nobody will check. Please prove me wrong.

Let’s recap: I’ve used only your tables and your own argument style to a.) debunk your claims on pertussis vaccination = infection, b.) shown how it can be used to show a vaccine induced 50% plus reduction in only 6 years [2001 – 2007] and c.) pointed out some curious gaps in your coverage of the data that don’t seem to support your claims.

I look forward to your reply,

Thank you,

Paul Gallagher

(emailed to Meryl Dorey on Jan. 7th, 2012)

Second ABC complaint upheld: Meryl Dorey “distorted and selectively presented information” on pertussis vaccination

Unfortunately, she (Meryl Dorey) added little and took the opportunity to promote a case against the use of the pertussis vaccine based on distorted and selectively presented information.

♦ ABC Audience & Consumer Affairs, December 19th, 2011 ♦

Readers of musings and mumblings here may remember a look at one Meryl Wynn Dorey’s “ABC of immunisation lies“, following Nicola Roxon’s Immunisation Incentive announcement.

Ms. Dorey kicked off deceiving Terri Begley’s audience on Mornings, November 15th on ABC 612. As covered by reasonablehank in ABC Complaint upheld – Meryl Dorey “disingenuous” and “added little” with “unsubstantiated claims”, a complaint was lodged and upheld by ABC Corporate Affairs.

In the afternoon Dorey popped up again on ABC 666 Drive speaking with Louise Maher. Again she seized the opportunity to launch into rapid fire fiction on pertussis infection and vaccine efficacy. This trick has been picked apart a few times here. So, I shot of a long complaint with references, tables and tactics laid out. To my delight the dedicated folk at ABC Audience and Consumer Affairs waded through it and the complaint was upheld. With their permission I’ve copied the response below.

The only other point (related to media correspondence) I’d like to cover is that I also sent a synopsis of Dorey’s pertussis and autism tricks to Tiga Bayles prior to her appearance on his Let’s Talk show. It had my name, phone number and email address. He didn’t raise any of the points as Dorey recited exactly what I’d warned him she would, choosing to feign surprise and smooth her path. He did however mention “the haters” and “sad small-minded people” who “hide behind anonymity too”.

Dorey agreed that her opponents were “cowards”, members of a “hate group” and guilty of a range of lousy transgressions, primarily around suppressing free speech. Without sounding too small minded, I did feel this was most unhelpful on Tiga’s part. Others also wrote openly to him and still more had articles published on widely read publications, such as The Drum and Mamamia. Meryl Dorey’s critics are not anonymous.

With that out of the way, we can enjoy knowing that both of Dorey’s appearances on ABC on November 15th have resulted in upheld complaints.

Reprinted with permission of ABC Audience and Consumer Affairs.

Dear Mr. Gallagher,

Thank you for your email of November 27 concerning the interview of Meryl Dorey conducted by Louise Maher on radio 666.

As your correspondence raised concerns of misleading and inaccurate content, your email was referred to Audience and Consumer Affairs for consideration and response. The unit is separate and independent from ABC program areas and is responsible for investigating complaints alleging a broadcast or publication was in contravention of the ABC’s editorial standards. In light of your concerns, we have reviewed the broadcast and assessed it against the ABC’s editorial requirements for accuracy, as outlined in section 2 of the ABC’s Editorial Policies: In the interests of procedural fairness, we have also sought and considered material from ABC radio.

On Thursday November 24 Louise Maher spoke to the ACT Chief Health Officer Dr Paul Kelly about a measles outbreak at a Steiner school in the ACT.  The following day she looked at the government’s announcement that day that from July 2012 up to $2100 of the family tax benefit per child will be conditional on a child being immunised, and spoke to Dr Julie Leask, from the National Centre for Immunisation Research and senior lecturer at the School of Public Health at Sydney University and Meryl Dorey from the Australian Vaccination Network.

The program team believed that Ms Dorey would have something to add to the discussion about the Government’s initiative. Unfortunately, she added little and took the opportunity to promote a case against the use of the pertussis vaccine based on distorted and selectively presented information. As this was not anticipated, the presenter was not in a position to effectively challenge Ms Dorey’s assertions. To her credit, Ms Maher recognised this and acted to get expert advice to air from the Chief Medical Officer of the ACT.

That interview was ultimately aired on the following Monday. The effect of that delay was to potentially mislead listeners about the effectiveness of the pertussis vaccine. This was exacerbated by the fact that the introduction to Ms Dorey did not adequately contextualise Ms Dorey’s comments by informing listeners that she is a campaigner against vaccination who has no medical qualifications and her organisation has been the subject of a warning by the NSW Health Care Complaints Commission for providing misleading information to the public.

Notwithstanding the team’s efforts to address claims made by Ms Dorey, it is our view that she wasn’t introduced with sufficient context to ensure listeners were not misled by her unsubstantiated claims.

Radio management apologises for this lapse. It advises that it will again communicate to radio staff the importance of providing listeners with all relevant context and information when presenting controversial and potentially dangerous viewpoints – particularly if they propose to interview Ms Dorey again.

Accordingly, Audience and Consumer Affairs conclude the broadcast was not in keeping with the ABC’s editorial standards for accuracy as outlined in section 2.1 of the ABC’s Editorial Polices. Please be assured that your comments and this decision have been conveyed to ABC Radio management and the producers of the program.

Thank you for taking the time to write; your feedback is appreciated.

For your reference, the ABC Editorial Policies are available online at

Should you be dissatisfied with this response to your complaint, you may be able to pursue your complaint with the Australian Communications and Media Authority,

Yours sincerely


Audience & Consumer Affairs

  • Louise Maher receiving “distorted and selectively presented information” on the use of the pertussis vaccine:

MP3 file for download here.

Meryl Dorey’s upcoming Woodford Festival whooping cough trick

At risk of flogging a dead myth it’s worth keeping up deconstructing Meryl Dorey’s falsehoods as they keep arising.

In the near future on radio and most likely at Woodford, Dorey will trot out the old shuffled pertussis vaccination vs notification statistics to argue the vaccine is ineffective. The pertussis trick has been a standard for years but since September 2009, we’ve had access to her data sets when she used them in response to the HCCC regarding complaints raised about her. I’ve looked at each incarnation of this trick, which has scarcely changed.

Her claim begins by pointing out that in 1989-90 just before compulsory notification of pertussis began in 1991, immunisation was 71% (figure 1). This figure is sourced from the top table below, which provides figures from 3 ABS surveys of children 0 – 6 years. [Zoom resolution here].

The bottom table shows that coverage has risen to 95% for the cohort January 1st – March 31st, 2006 in children 2 years and under. It’s from Communicable Diseases Intelligence 2007;31:333. It also informs us the assessment date is June 30, 2008. You can find the same here in Dorey’s submission to the HCCC on page 6.

Figure 1

In replying to the HCCC Dorey referred to the National Notifiable Diseases Surveillance System (NNDSS) figures for pertussis which now includes data to 2011 (Figure 2). [Zoom resolution here]. Her claim continues on, using the two data sources. Although retold countless times, I’ll be scrupulous and quote from Dorey herself on page 6 of her HCCC reply:

Since the AVN was established, Australia has experienced an increase of over 23% in our rate of vaccination against whooping cough with a concurrent increase in the incidence of this disease of almost 40 times. Please refer to the Australian government graphs below:

For our purposes these “government graphs” are figures 1 and 2. Sure enough, as we can see below the notification rate in 1991 is 332 and the rate in 2008 is 14,292. But… 2007 has a rate of only 4,864, 2006 has a rate of 9,764. 2005 has a rate of 11,165. And 1996 (12 years earlier) has a rate of 12, 237.

What we see going back are the peaks and troughs associated with pertussis infection and control familiar to the developed world. We also know the present epidemic began in 2008. Before this, 2007 had the least notifications in eight years. In fact according to this table (pertussis per 100,000) it’s the lowest since 1992.

Figure 2

The operative words here are “concurrent increase”. Ms.Dorey frequently palms this off as a steady, correlating increase in infection when the figures show nothing of the sort. There are many problems with this approach. She is using entirely unrelated data sets. The NNDSS data tell us nothing about vaccination or immunity of subjects. There are 18 age groups in NNDSS data. One of Dorey’s vaccination tables in figure 1 covers two age groups only, the other table covers half of the youngest NNDSS age group.

The 1991 and 1992 notification figures are so low as to be anomalies. This is the normal when a disease is placed on the “notifiable” list and practitioners adjust to new requirements.

But now, let’s return to the ABS pertussis vaccination figures Dorey kindly provided. After a slight drop from the 71% she kindly points out, we reach 2001 – a full decade after notifications began – with a pertussis vaccination rate of only 71.6%. This is most cunning on Dorey’s part.

A 0.6% increase in ten years. Why even bother with the first decade? Why not choose 2001 with a notification rate of 9,541 (almost twice that of 2007)?

Clearly it is rank selection of data to convey a falsehood about pertussis vaccination. Exactly as the HCCC have stated. Applying Ms. Dorey’s logic to 2001 and 2007 vaccination and notification rates one can argue a reduction of almost 50% in pertussis infection, with virtually the same increase in immunisation levels. We can see with rising vaccination there has been no “corresponding increase in the incidence of this disease”.

In fact, we have 71.6% coverage in 2001. And 95% in 2006. Both provided by Dorey. That’s five years, but she chooses to cite the 1990 figure of 70% from the upper table, and the assessment date of June 2008 in the lower table of figure 1. Why? Because the initial year of notification (1991) is absurdly small, and 2008 is the beginning of an epidemic.

Indeed, a close look at notification rates in Figure 2 shows comparable rates in the first and second decades, excluding only the epidemic which began in 2008. Ms. Dorey really needs to explain how these figures can be expected to justify her claim.

Next comes age groups, and our understanding as to why Dorey never mentions them. Most infections in Australia are in adults with no immunity. Her 95% in figure 1 applies only to under 2 year olds. This is half of one age group out of the 18 provided by the NNDSS. We know immunity begins to wane certainly by about age ten (if not earlier) and that adults are definitely in need of a booster. In effect most pertussis notifications are from those with no immunity. Figure 3 is pertussis notifications for 2007 (pre-epidemic) by age and sex [Zoom here]:

Figure 3

In any year (including epidemic years) most notifications come from adults. Rather than pointing to total figures Ms. Dorey should be honest and admit that most infections come from the adult population with an immunisation rate of only 11.3%. See page 18, Adult Immunisation Survey. This is insufficient to provide herd immunity.

Adults may show no symptoms or very mild symptoms and not seek any care. What this means is that adult infection levels are higher than notification levels. It’s important to stress that Meryl Dorey will cite infant or childhood vaccination levels, but most notifications come from adults. Ms. Dorey’s claim of total infections casting doubt on 95% of childhood vaccination is again found wanting.

The fact that 0 – 4 is the highest childhood age cohort and comparable with adults of over 30 is due to newborns being unvaccinated and not completing the schedule for many weeks. This places them at extended risk.

So, even giving Dorey’s dodgy data sets a fair run they still fail on a number of fronts to deliver the goods. In fact they undermine her so-called proof. Infections come from non immunised, and as we’ll see below reduction in childhood immunisation is catastrophic. She has some explaining to do.

We know the pertussis vaccine is not a magic bullet and that vaccinated children can catch pertussis as immunity wanes. In general they develop much milder symptoms and are not at risk of death and disability as are unvaccinated infants and small toddlers. It is crucial to ensure vigilance against waning immunity. Boosters should be considered.

Low immunisation levels have been linked to the present outbreak. Tragically it’s been known for quite some time that this epidemic is likely to have begun in Meryl Dorey’s backyard – where she has her greatest influence. The SMH reported in October 2010:

The highest rates of so-called “conscientious objectors” to immunisation are in parts of the north coast – such as Byron Bay – where 12 per cent of children born between 2001 and 2007 were never immunised for any condition. […]

An epidemic of whooping cough in 2008 and 2009 began on the north coast. It quickly swept across the state driven by low vaccination rates in some wealthy parts of Sydney. Low-income areas in western Sydney also had less immunisation and were linked to outbreaks, Dr Menzies said.

California is also experiencing an epidemic on the back of reduced immunisation levels. Dorey recently posted this Californian article about waning pertussis immunity on Facebook, claiming it indicated an ineffective pertussis vaccine. She omitted Dr. Carol Baker:

In QLD where Woodford holds it’s festival? From November last year. Outbreak in QLD as parents snub vaccination:

PARENTS who refuse to vaccinate their children are contributing to the worst whooping cough outbreak on record in Queensland, with notifications likely to exceed 7000 this year.

Four to 8 per cent of children on the Sunshine Coast are registered as so-called “conscientious objectors”, meaning their parents refuse to immunise them. […] Whooping cough is deadly to babies who are too young to be vaccinated. One in 200 babies who contract whooping cough will die.

The advice from all states and federal health authorities is to immunise and ensure immunity is up to scratch with boosters. The outbreak in Australia is due to low immunisation levels and waning immunity in children who have been vaccinated.

The last person to trust is Meryl Dorey.