Immunisation recommendations for the older population

There are a variety of factors that need to be considered in relation to the vaccination of the older population. A gradual decline of the immune system occurs as people age (known as immunosenescence), impacting how the immune system responds to new infections, as well as the effectiveness of long-term immune memory. It is for this reason that some vaccines are specifically designed for the older population and aim to enhance the immune response by using higher immunogenicity formulations or by containing adjuvants. Providing optimal protection can also be complicated due to the increasing prevalence of multiple comorbidities in the aging population. Specific medical conditions or targeted therapies (eg. chronic renal conditions, chemotherapy for cancers etc) can also cause older adults to be more vulnerable to infections and their complications. Further to this, relying on patient recall, as well as a lack of awareness for the recommended vaccines for the older population, can result in either missed vaccines or additional unnecessary doses being administered.

There are multiple vaccines recommended for the older population as outlined below.

Herpes zoster (Shingles) vaccine

Shingles is caused by a reactivation of the varicella virus and will occur in approximately 20-30% of people in their lifetime. Older people (> 70 years of age) are more likely to suffer post-herpetic neuralgia (PHN) following a shingles infection than younger people. PHN is a chronic neuropathic pain which can affect 1 in 4 cases of shingles diagnosed in those > 80 years. It can persist for months to years with pain control being difficult to manage, impacting quality of life.

Zostavax® has been shown to reduce the incidence of developing shingles by up to 50%, as well as the incidence of PHN in those ≥ 60 years of age by 66%. It is currently funded under the National Immunisation Program (NIP) for persons aged 70 years, with a catch-up program for those aged 71–79 years also funded (until October 2021). As it is a live-attenuated vaccine, it is contraindicated for use in those who are immunosuppressed, or on immunosuppressive medications (eg; Rituximab, Azathioprine, Prednisolone, chemotherapy etc). Prior to administering Zostavax® it is important to take a thorough patient history to determine suitability for immunisation. Further guidance can be provided by reviewing MVEC’s Zostavax GP decision aid or by contacting SAEFVIC prior to immunisation.

Pneumococcal vaccines

Invasive pneumococcal disease (IPD) can manifest as meningitis, pneumonia and bacteremia, with severe disease requiring hospitalisation, causing significant morbidity and even death. The elderly (along with infants) are at the highest risk of developing IPD. Recommendations for pneumococcal vaccines in adults vary according to age and medical condition [refer to ATAGI clinical advice on vaccination recommendations for people with risk conditions from 1 July 2020]. Pneumococcal vaccines are currently provided for free on the NIP for the following people:

  • Aboriginal and Torres Strait Islander adults with NO risk condition - 1 dose of Prevenar 13® at 50 years of age, followed 8 weeks later by 2 doses of Pneumovax 23®, given 5 years apart
  • Non-indigenous adults with NO risk condition - 1 dose of Prevenar 13® at >70 years
  • Non-indigenous adolescents/adults diagnosed with a risk condition - 1 dose of Prevenar 13® at diagnosis, followed by 2 doses of Pneumovax 23®, given 5 years apart

In adults, injection site reactions may occur > 3 days following the Prevenar 13® dose given at > 70 years, particularly in those who have previously received Pneumovax 23 ®. A history of large local injection site reactions following previous pneumococcal vaccines is not a contraindication to further doses.

Refer to MVEC: Pneumococcal vaccines and diseases for more information.

Influenza vaccines

For older adults, and those with certain medical conditions (eg. chronic lung disease, cardiac disease, immunosuppression), influenza disease can cause serious morbidity and mortality. Annual influenza vaccination is strongly encouraged and it is available for free on the NIP for those ≥ 65 years of age and/or adults with certain medical conditions. Due to a reduced immune response to routine influenza vaccines, those aged ≥ 65 years should receive higher-immunogenicity influenza vaccines.

Refer to MVEC: Influenza vaccine recommendations for specific information on brands and dosing.

COVID-19 vaccines

Older people and those with comorbidities (eg. hypertension, diabetes, chronic lung disease etc) are much more likely to suffer from severe COVID-19 disease if infected. Of those who are > 80 years of age and have COVID-19 disease, approximately 1 in 3 will die from it.

Currently in Australia there are 2 vaccines approved for use to prevent severe COVID-19 disease. They are available for free, with older populations in the earlier priority groups identified for eligibility. Both vaccines have been recommended by the TGA for use in older people, with no upper age limit for either vaccine.

Clinical trial data has shown that Comirnaty™ has the same efficacy for the older population as it does for younger people. COVID-19 AstraZeneca™ also induces a strong immune response in the older population, however currently available clinical trial data has not been able to conclusively determine vaccine efficacy in this age group due to the small numbers of > 65 year old adults enrolled in initial trials. Further data on older people in AstraZeneca trials will be available in the coming months.

The current recommendation for COVID-19 immunisation of adults > 65 years with underlying health conditions should be decided on a case by case basis, in consultation with a medical professional

For more information on COVID-19 vaccination for older people please refer to COVID-19 vaccination – COVID-19 vaccination decision guide for frail older people, including those in residential aged care facilities.

Reporting to the Australian Immunisation Register (AIR)

The AIR provides a record of all vaccine doses given, the date of administration as well as the specific brands used. Since 2016 vaccines administered to Australians of any age have been recorded onto the AIR. Patient recall, particularly in the older population, is not reliable and as such it important that immunisation records are accurately maintained and reviewed regularly.

From March 2021, new legislation came into effect making reporting vaccines to AIR mandatory. This includes all COVID-19 vaccines, influenza vaccines and all National Immunisation Program vaccines.

Refer to MVEC: Australian Immunisation Register for more information.

Resources

Authors: Daryl Cheng (Paediatrician, The Royal Children’s Hospital), Francesca Machingaifa (MVEC Education Nurse Coordinator) and Rachael McGuire (MVEC Education Nurse Coordinator)

Date: March 2021

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


University of Oxford/AstraZeneca COVID-19 vaccine

Name: COVID-19 Vaccine AstraZeneca (AZD1222 or ChAdOx1 nCoV-19)

Type: Viral vector vaccine (chimpanzee adenovirus vector)

Developer: Astra Zeneca

Recommended doses/interval: 2 doses, administered 12 weeks apart (noting a minimum interval of 4 weeks is acceptable)

Doses for Australia: 53.8 million doses, 3.8 million doses will be delivered to Australia in early 2021

Manufacturing: 50 million doses will be manufactured in Parkville, Australia in monthly batches by the local biotechnology company, CSL

Storage: Can be stored, transported and handled at standard refrigerator temperatures (2-8°C)

Background

The University of Oxford/AstraZeneca COVID-19 vaccine (ChAdOx1 nCoV-19) utilises a chimpanzee adenovirus (ChAdOx1) vector; which is unable to cause disease in humans. This viral vector has been tested for safety in other vaccines for Ebola, Middle East respiratory syndrome (MERS) and influenza. This vaccine utilises the full length SARS-CoV-2 spike protein DNA inserted into the viral vector.

On 16 February 2021, the University of Oxford/AstraZeneca COVID-19 vaccine (COVID-19 Vaccine AstraZeneca) was granted provisional registration in Australia by the Therapeutic Goods Administration for use in those ≥18-years of age for the prevention of COVID-19 disease caused by SARS-CoV-2.

Clinical trials

Pre-clinical (animal) trials were conducted in rhesus macaques, mice and ferrets. These trials showed that there were no adverse safety events, no evidence of immune enhanced inflammatory disease and a balanced immune response was induced. In animals, the vaccine appeared to reduce disease severity, but did not prevent infection or transmission (nasal shedding of the virus still occurred).

Phase 1/2 clinical trials were conducted in UK and recruited over one thousand participants in April and May 2020. Phase 2/3 clinical trials will be conducted in 50,000 participants globally (UK, USA, Brazil, South Africa and Kenya), with recruitment starting in July 2020. Interim results of Phase 3 studies, from over 10,000 participants, were published in the Lancet on 8 December 2020.

Safety profile

The Phase 1/2 results showed that the vaccine was safe but had higher reactogenicity than the control vaccine. Symptoms mainly occurred in the day following vaccination and self-resolved. Pain and tenderness at the injection site (83%), fatigue (68%) and headache (70%) were the most common symptoms in participants receiving the ChAdOx1 nCoV-19 vaccine. Fever occurred in 18% and flu-like symptoms of malaise (61%) and muscle ache (60%) were also common.

Phase 2/3 results showed similar reactions to those seen in Phase 1/2 trials but reactions were less common in older adults (aged over 55 years) and after the second dose. Most of the reported local and systemic adverse events were mild to moderate in severity.

Of the nearly 24,000 trial volunteers, only three of the 175 reported serious adverse events were possibly related to the vaccine and more than half of these events occurred in the control arm.

There have been two trial pauses due to initially unexplained illnesses; these were reviewed by independent experts before restarting the trials. One case of transverse myelitis was reported two weeks after ChAdOx1 nCoV-19 booster vaccination and was possibly related to vaccination. There were two additional cases of transverse myelitis that were determined to be unlikely to be related to vaccination by an independent committee of neurological experts. One case was due to pre-existing, but previously unrecognised, multiple sclerosis and the second case occurred in the control arm.

These Phase 3 trials were open to people with many underlying health conditions, however immunocompromised and pregnant people were excluded. Data is currently unavailable for children; they will be recruited in the later stages of Phase 3 trials, once extensive safety data is available from adult studies.

Immunogenicity

The ChAdOx1 nCoV-19 vaccine induced a specific antibody response to the SARS-CoV-2 spike protein after a single dose; this response was boosted after the second dose. Similar immune responses were seen across all age groups, including those aged 70 years and older. Regardless of age or vaccine dose, similar patterns were also observed with neutralising antibody responses and spike-specific T-cell responses.

Vaccine efficacy

Interim analysis of the Phase 3 trials was published on 8 December 2020. There were 11,636 participants (7,548 in the UK and 4,088 in Brazil) included in the interim primary efficacy analysis.

In participants who received two standard doses (5 × 1010 viral particles), vaccine efficacy was 62.1%. A subset in the UK trial received a half dose as their first dose and a standard dose as their second dose; in this cohort vaccine efficacy was 90.0%.

Overall vaccine efficacy across both groups was 70.4%. Further Phase 3 testing is underway to verify these results.

Vaccine efficacy in older age groups (over 55 years of age) could not be assessed in the interim analysis, but will be determined in future analyses once more data is accrued. This will be important data to review given the increasing morbidity and mortality seen with increasing age. Noting immunogenicity studies showed older adults do develop a robust immune response, similar to those seen in younger volunteers.

Resources

Authors: Daniela Say (MVEC Immunisation Fellow) and Nigel Crawford (Director SAEFVIC, Murdoch Children’s Research Institute)

Date: January 2021

Reviewed by: Rachael McGuire (MVEC Education Nurse Coordinator)

Updated: February 2021

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.