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No, combination vaccines don't overwhelm kids' immune systems

Aug 2017 - News

Kristine Macartney, University of Sydney, and Deputy Director NCIRS

Parents are concerned combination vaccines, which protect against several diseases at once, can be too much for a young immune system to cope with.

File 20170814 28423 ydm0mtfrom www.shutterstock.com

No parent likes seeing their child have injections. Yet, around 93% of parents across Australia protect their children against 15 serious diseases by giving them all the recommended vaccines on the National Immunisation Program Schedule. This success is due in part to the value of combination vaccines, which protect against two or more diseases in one go.

Combination vaccines mean kids need fewer injections overall. By adding several antigens (the part of the germ that stimulates the immune system) together in one vaccine, we can protect kids against up to six diseases in a few shots. These shots are typically given in a series of two or three injections over time.

Our new study released today in JAMA Pediatrics, backs the safety of a four-in-one combination vaccine – designed to protect against measles, mumps, rubella and varicella (chickenpox) and known as the MMRV vaccine. We also show its added benefits in protecting kids by the time they reach pre-school.


Read more: Six myths about vaccination – and why they’re wrong


Making a combination vaccine typically involves decades of research to ensure the precise balance of “active” components is included, the immune response to each component is effective, and even the slightest change in a vaccine doesn’t change its safety profile.

This is stringently regulated across the world, by groups such as the Therapeutic Goods Administration in Australia and Food and Drug Administration in the USA, before a vaccine is even trialled in humans, or indeed ultimately licensed for use.

This video, from the Children’s Hospital of Philadelphia, outlines the steps taken to develop, and evidence behind, combination vaccines.

Once these combination vaccines are used, their safety (as well as the safety of other vaccines) is also actively monitored. One new way we do this in Australia is by monitoring any side-effects in real time. Parents respond to an SMS survey about their child’s recent vaccination, the results of which are collated and posted online.

Too much to handle?

However, some parents question if giving an injection that protects against multiple diseases will overwhelm the immune system or be too much to handle. The answer is “no” for many reasons.

A review into parental concerns about combination vaccinations confirms the moment babies enter the world they are covered in millions of foreign germs. The infant immune system is no longer considered “immature” but is finely tuned to respond to the incredible number of viruses, bacteria and other things it meets early in life. Vaccines contain just a few antigens compared to what babies meet every day.

The researchers estimate that even if 11 vaccines were given to infants at one time, only about 0.1% of the immune system would be “used up”.


Read more: Explainer: how does the immune system work?


Rather than weaken the immune system, or putting it under strain, vaccines train the infant immune system to respond, without causing the terrible consequences of the disease itself. Combination vaccines do the same.

The design of vaccines has been increasingly tailored to leverage this unique biology, including the development of new combination vaccines.


Read more: Vaccine program changes protect kids, but with fewer ouches


For instance, in 2013, two new combination vaccines – the MMRV vaccine and a combination vaccine against the Haemophilus influenzae type b and meningococcus type c bacteria (Hib-MenC) – were added to Australia’s immunisation schedule, reducing the number of injections babies needed.

Tackling four diseases at once, and measles

Our new study evaluated the impact of one these – the MMRV vaccine – since it was added to the schedule.

Before the MMRV vaccine was introduced, kids were protected against varicella (or chickenpox) with a separate vaccine. And they received their second dose of measles-mumps-rubella (MMR) vaccine at age four years, quite a big gap after their first-birthday dose of MMR.

By introducing this combination MMRV vaccine earlier (at 18 months), our study showed the second dose of vaccine against measles provided early comprehensive protection against this deadly disease.

While the first vaccine dose (given at 12 months) only gives a full immune response in about 90% of children, giving a second dose boosts immunity to more than 95% and also helps to provide longer lasting protection.

The MMRV combination vaccine means more children are protected against chickenpox, mumps and rubella (german measles) before entering pre-school. www.shutterstock.com

Our study showed not only that the percentage of children fully protected against all four diseases is now greater compared with when MMR was separated from the varicella vaccine, it is also occurring at a much earlier age.

“On time” vaccination (within 30 days of the recommended age) has now improved by 13.5% (from 58.9% to 72.4% of children). This means many more children are protected against measles, chickenpox, mumps and rubella (German measles) before entering pre-school.

Tackling four diseases at once, and safety

Another important part of our evaluation was to ensure that introducing this vaccine was safe. If the combination MMRV vaccine is given as the very first dose of measles-containing vaccine in very young children, it causes more cases of fever and a small increase in febrile seizures (a common, usually benign, but frightening convulsion in children) compared with giving the vaccines separately.

Our study examined if using the MMRV shot in the Australian program as the second dose would be linked to an increase in febrile seizures. When we examined all children who came to paediatric hospitals across the country with a febrile convulsion, then looked at what vaccines they had received, we found no increase in febrile seizures associated with this second dose given at 18 months.

So introducing this combination vaccine in 2013, which has taken decades to develop, has:

  • reduced the number of injections children need
  • helped improve the total number of children vaccinated on time, and
  • has been safe.

In a nutshell

Combination vaccines not only mean fewer visits to the doctor or nurse for injections, they can have other benefits, as well as being safe.

Our study highlights how much information is considered before making any change to the immunisation schedule to introduce combination vaccines, and importantly, how carefully changes to the schedule are monitored and evaluated.

The ConversationWhile combination vaccines might introduce extra antigens to a child’s immune system in one go, they are a tiny, tiny proportion of what children meet as they grow. Being vaccinated trains a child’s immune system to withstand some of the biggest and baddest germs they will encounter.

Kristine Macartney, Associate Professor, Discipline of Paediatrics and Child Health, University of Sydney

This article was originally published on The Conversation. Read the original article.


Media Release: 4-in-1 Combination Vaccine Improves National Vaccination Uptake

Aug 2017 - News

Nationwide on-time protection against measles and other diseases has increased by more than 13 per cent since the introduction of the 4-in-1 measles-mumps-rubella-varicella (MMRV) vaccine for toddlers in 2013, a recent study has revealed.

According to the study, which was carried out by the Paediatric Active Enhanced Disease Surveillance (PAEDS) in conjunction with The National Centre for Immunisation Research and Surveillance (NCIRS), the uptake of on-time measles-containing vaccinations has increased nationally by 13.5% over the last four years, when the MMRV vaccine was first introduced into the National Immunisation Program (NIP).

Prior to July 2013, MMRV vaccines were not used in Australia. Two doses of measles-mumps-rubella (MMR) vaccines were scheduled on the NIP at ages 12-months and 4 years, similar to the US and UK schedules. In an effort to increase the population-level vaccine coverage as well as protection for each individual child, the scheduled age for the second MMR dose was brought forward to 18 months (after the first dose of MMR at 12-months) and replaced with MMRV vaccine.

Deputy Director of Government Programs at the NCIRS and paediatric infectious disease consultant Associate Professor, Kristine Macartney says, “Since implementing the compressed immunisation schedule at ages 12 and 18 months, there has been a 13.5% nationwide improvement in coverage and on-time vaccinations against all four diseases. We have also demonstrated that more children were fully protected against measles at an earlier age.”

“From a family’s perspective, a 4-in-1 vaccine is much more convenient and helps with vaccine acceptance, coverage and ultimately, disease control. Moreover, use of MMRV vaccine as dose 2 of measles containing vaccine (MCV) at the age of 18 months is proven to be a safe way to prevent these diseases. In overseas studies, use of this as dose 1 gave rise to more fever and febrile seizures than had been seen before. However, we have proven that using it under the NIP as dose 2 doesn’t cause seizures,” she added.

Australia was one of the first 4 countries in the World Health Organisation Western Pacific Region to reach measles elimination status, officially declared in March 2014(1). Global efforts to control measles rely on achieving and maintaining high 2-dose vaccine coverage of more than 95% at a country and district level(2). Introducing this 4-in-1 combination vaccine at the younger age of 18 months should help us to maintain that elimination status.

Read the full article here


(1) Gidding HF, Martin NV, Stambos V, et al. Verification of measles elimination in Australia: application of World Health Organisation regional guidelines. J Epidemiol Glob Health. 2016;6(3):197-209
(2) Bester JC. Measles and measles vaccination: a review. JAMA Pediatr. 2016;170(12):1209-1215

Media contact: Sheri Locmayon
Public Relations Department
The Children's Hospital at Westmead
P: (02) 9845 3364
E: sherilyn.locmayon@health.nsw.gov.au


Influenza Vaccine Safety Surveillance Data Update

Jul 2017 - News

In 2017, four age-specific quadrivalent influenza vaccines are available under the National Immunisation Program (NIP). The current safety profile of the 2017 vaccines is reassuring and consistent with expectations. As at 30th July 2017 almost 70,000 people have participated in active influenza vaccine safety surveillance via SMS/email representing a 72% participation rate. Real-time, patient reported data on the safety of Zoster vaccine and Pertussis booster vaccines in children is also available.

View the current AusVaxSafety surveillance data


July 2017 - Newsletter

Jul 2017 - Newsletters

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NCIRS at the Communicable Diseases Conference

Jun 2017 - News

The Communicable Diseases Control (CDC) Conference 2017, convened by the Communicable Diseases Network Australia, the Public Health Laboratory Network and the Public Health Association of Australia, was held in Melbourne from Monday 26 to Wednesday 28 June 2017. A/Prof Kristine Macartney, Deputy Director, NCIRS was an opening keynote speaker and presented on 'What we have learned from 10 years of PAEDS'. NCIRS staff also presented work in the areas of epidemiology, program evaluation, serosurveillance and vaccine safety. Highlights from the conference can found on Twitter. View NCIRS presentation highlights on the NCIRS Twitter page.  Select presentations are available on the CDC conference webpage.


PAEDS 10 Year Anniversary Showcase

Jun 2017 - News

PAEDS Investigation Nurses at the 10 Year Anniversary Showcase

In June 2017 Paediatric Active Enhanced Disease Surveillance (PAEDS) investigators, nurses and key stakeholders came together in Melbourne to discuss and present their work of 10 years in an anniversary showcase. PAEDS, originally founded through a collaboration between the Australian Paediatric Surveillance Unit (APSU) and NCIRS has grown to surveillance at 7 sites across Australia, focusing on vaccine preventable diseases and serious childhood conditions of public health importance: Acute Flaccid Paralysis, intussusception, pertussis, varicella, febrile seizures, encephalitis, influenza and most recently meningococcal disease and group A streptococcal disease. Progress and outcomes from research into these conditions was presented at the showcase. PAEDS also celebrated Dr Philip Britton’s PhD award for investigation of acute childhood encephalitis, as well as a recently achieved NHMRC partnership grant that will support additional research into understanding why children become unwell with influenza and pertussis. Congratulations to PAEDS on 10 years and many wonderful achievements yet to come.

More information »

Immunisation: it’s not just for kids

Jun 2017 - Medicine Today; 18(6): 25-33 - News

In this article by Dr Lucy Deng, Ryan Macdougall, A/Prof. Kristine Macartney published in Medicine Today June 2017; 18(6): 25-33 the authors focus on the important, and sometimes overlooked, area of adult vaccination.

Abstract

In an ageing population with a high burden of vaccine-preventable diseases, vaccines are equally as important in adults as they are in children. Although there are many potential barriers to adult vaccination, these can be addressed, and every healthcare provider should routinely review the immunisation status of their adult patients as part of health promotion.

Key Points
  • Adults may require vaccines for multiple reasons, including incomplete childhood schedules, waning immunity, medical and lifestyle risk factors, occupation-related risks, travel and migration.
  • The majority of undervaccinated people in Australia (those who are eligible for vaccines under the National Immunisation Program but do not receive them) are adults.
  • Vaccines are one of the key components to healthy ageing, given the high burden of vaccine-preventable diseases in the older population.
  • More vaccines are becoming available and are recommended for the adult population, including zoster vaccine for adults aged 70 to 79 years.
  • Barriers to the delivery of adult vaccinations include cost, lack of documentation of doses previously received and public misconceptions about the need for vaccination in adulthood.
  • The ‘HALO’ (Health, Age, Lifestyle, Occupation) principle can be applied when assessing vaccine requirements for adults.
  • The Australian Immunisation Register, introduced in 2016, aims to capture all immunisations across the lifespan of a person.

Click here to access the full article


Congratulations to Cristyn Davies and Samantha Carlson, NCIRS recipients of NSW Health PhD Scholarships

Jun 2017 - News

Congratulations to Cristyn Davies and Samantha Carlson, recipients of the NSW Health PhD Scholarship. This scholarship supports PhD candidates to gain skills and undertake projects that will build capacity in the NSW Health system in areas of identified need.

Based on the findings of a completed study about human papillomavirus (HPV) vaccination in 40 Australian secondary schools (HPV.edu) funded by the National Health and Medical Research Council (NHMRC), Cristyn is investigating how a well-designed HPV vaccination intervention led to changes in knowledge and attitudes in adolescents and parents/guardians. She is also examining mechanisms within the school based vaccination environment for intervention effect, and will work collaboratively with key stakeholders to translate these findings into policy and assist best practice, and measure the effectiveness of these changes. Cristyn is supervised by Prof Rachel Skinner (USyd), A/Prof Kristine Macartney (NCIRS), and A/Prof Melissa Kang (UTS).

Through the Paediatric Active Enhanced Disease Surveillance (PAEDS) network, Samantha is investigating why children get severe influenza and pertussis, and is supervised by A/Prof Julie Leask (USyd) and A/Prof Kristine Macartney (NCIRS).  This project uses mixed-methods research with parents of children who have been hospitalised for influenza and pertussis. Guided by the social ecological model (SEM), the research will determine how social networks, organisations, communities, and policies influence a parent’s decision and action to vaccinate their child against influenza and pertussis. Results will be used to develop a causal pathway as well as practical recommendations to prevent children acquiring these vaccine preventable diseases.


2015 Annual Immunisation Coverage Report

May 2017 - News

The latest NCIRS national Annual Immunisation Coverage Report is now available along with a summary PDF document of key findings and accompanying PDF slideset document containing all tables and figures from the report. View the report here


Updated Factsheets

May 2017 - News

The following fact sheets have been updated and are now available on our factsheets webpage

Influenza vaccines for Australians [PDF – 573kB]

Vaccines for Australian adults [PDF – 309kB]

Meningococcal vaccines for Australians [PDF – 741kB]


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