Hyposplenia

Background

The spleen plays an important role in fighting infections by removing bacteria from the blood stream, in particular, encapsulated bacterial infections. It acts as a filter, breaking down damaged or old red blood cells and also stores red blood cells and platelets which are released in the instance of severe blood loss.

What is Asplenia?

People with no spleen (asplenia) or who have a spleen with decreased or absent function (hyposplenia) are at an increased risk of infection with encapsulated bacteria, most importantly Streptococcus pneumoniae (pneumococcus), the cause of invasive pneumococcal disease (IPD) which includes: meningitis (brain infection); septicaemia (blood infection) and pneumonia (chest infection). Infections with other bacteria, such as Neisseria meningitidis (meningococcus) and Capnocytophaga canimorsus (after dog or cat bite) also occur at an increased rate in people with asplenia.

Children with congenital asplenia, cancer related asplenia and those with sickle cell anaemia are at greater risk of infection than those who have had splenectomy for trauma.

The first two years following splenectomy are considered the highest risk for infection, although several reports indicate that the risk is lifelong.

Immunisation in people with asplenia

Due to the increased risk of infection it is essential that a person without a functioning spleen remain up to date with immunisations. Many of these infections are vaccine preventable, and protection can be optimised by appropriate and timely immunisation.

Individuals without functioning spleens are not at an increased risk of contracting influenza, however, vaccination with the annual seasonal influenza vaccine is recommended as contracting influenza increases the risk of developing a secondary bacterial infection.

Recommended vaccines

It is recommended that people with functional or anatomical asplenia, including sickle cell disease or other haemoglobinopathies receive the following vaccines which are funded under the NIP:

  • Pneumococcal
    • 13-valent pneumococcal conjugate vaccine (Prevenar 13®)
    • 23-valent pneumococcal polysaccharide vaccine (Pneumovax 23®)
  • Meningococcal
    • Meningococcal quadravalent conjugate vaccine 4vMenCV (Nimenrix®)
    • Meningococcal B recombinant multicomponent vaccine MenBV (Bexsero®)
  • Haemophilus influenzae type B
  • Annual influenza vaccine

NB: From 1 July 2020 there have been changes to the National Immunisation Program (NIP) involving recommendations and funding for vaccine schedules for individuals with risk conditions [see ATAGI: Clinical advice on changes to vaccine recommendations and funding for people with risk conditions from 1 July 2020]

MVEC have worked with the Spleen Australia team to develop comprehensive vaccination guidelines [see Resources below].

Resources

Authors: Nigel Crawford (Director, SAEFVIC, Murdoch Children's Research Institute), Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children's Research Institute)

Reviewed by: Francesca Machingaifa (SAEFVIC Research Nurse, Murdoch Children's Research Institute) and Georgina Lewis (Clinical Manager SAEFVIC, Murdoch Children's Research Institute)

Date: July 2020

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.


How to set up a drive-through immunisation clinic

Drive-through immunisation clinics are an alternative venue for supporting vaccine delivery. A drive-through clinic can assist members of the community to continue to receive recommended immunisations whilst maintaining physical distancing.

A drive-through clinic may not be a setting that is recommended for all patients. It is important that patients be screened for their suitability to use a drive-through service prior to immunisation. Pre-screening of patients can identify previous immunisation reactions, history of vasovagal reactions or needle phobia.

Running sessions by appointment may allow for planning the type and amount of vaccines required and also allows the flow of patients to be staggered in order to prevent traffic congestion.

Preparation for drive-through clinics

There are many different factors that need to be considered when setting up for this type of immunisation venue.

The location:

Consider a location within close proximity of the GP service or health care facility (if applicable). An ideal location would allow for a 1-directional flow of traffic in order to avoid congestion and ensure the safety of roaming staff members. Each individual parking bay should allow enough room for all 4 car doors to completely open without any obstructions (to ensure full access to each patient should AEFI occur).

Equipment:

Carefully consider the equipment required to set up and maintain a drive-through clinic. Equipment should include clear signage, bed/chair to manage adverse events if required, an anaphylaxis response kit, essential paperwork, (such as pre-immunisation checklists and vaccine side effects forms), equipment to maintain the cold chain, as well as any equipment necessary to prepare and administer vaccines. Remote access to patient records and the Australian Immunisation Register (AIR) is recommended to allow for review of immunisation records. as well as appropriate documentation of any vaccines administered.

Staff:

Staff may include nurse immunisers, as well as medical and administrative personnel.

The cold chain

Storage of vaccines in a drive-through clinic setting must comply with the cold chain recommendations set out by the vaccine manufacturer.  The time between vaccines being removed from purpose-built vaccine fridges to being administered should be as short as possible.

During a drive-through immunisation session

Immunisation history, pre-immunisation checklist, possible vaccine side effects and suitability for immunisation must be reviewed and discussed prior to vaccination.

Emergency equipment (anaphylaxis response kit) and a telephone must be readily available should they be required.

Correct injection technique is essential, ensuring that the entire limb is exposed and correct anatomical landmarks identified to locate the correct injection site. If a patient cannot be safely immunised in the car (eg: child seated in the middle car seat) or is not a suitable candidate for in-vehicle immunisation then they could be immunised out of the car in a chair, then returned to the car to wait for the recommended 15 minute waiting period. Patients should be advised not to get in and out of their cars whilst parked.

Post-immunisation in a drive-though session

Following immunisation, patients must remain at the vaccination venue for at least 15 minutes and should be advised to avoid driving for at least 15 minutes following vaccination. Patients waiting in their vehicles should be instructed to use the car horn to gain attention in their 15 minute observation period if required. All vaccines should be recorded on the AIR and appropriate documentation should be completed and provided to the patient.

Resources

Authors: Francesca Machingaifa (SAEFVIC Research Nurse, Murdoch Children’s Research Institute) and Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute)

Date: 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.

 

 


Hypotonic-hyporesponsive episode (HHE)

A hypotonic-hyporesponsive episode (HHE) is defined as the sudden onset of muscle limpness (hypotonia), reduced responsiveness or unresponsiveness and pallor or cyanosis occurring after vaccination in early childhood (< 2 years of age).

Most children are initially irritable and febrile prior to the event and respiration may be shallow during the event. HHE's can be immediate or delayed. The immediate HHE's are often preceded by crying, breath holding and are like an immediate vasovagal phenomeneon. Close inspection is required to ensure there are no features suggestive of an allergic reaction. The delayed reactions usually occur 1 to 48 hours after vaccination and resolve spontaneously; the median episode duration is 6-30 minutes. Diagnosis of HHE is made clinically and often no investigations are required.

This occurs where no other cause is evident, such as seizure or anaphylaxis. This is distinguished from a vasovagal-syncope (fainting episode), which presents with similar signs and symptoms but occurs soon after vaccination (< 5mins) and usually occurs in an older age group (≥ 2 years of age).

The pathogenesis of HHE is unknown but is likely to be multifactorial. HHE is rare and results in transient signs, and hence, there are limitations to investigation.

Associations and incidence

HHE has been documented to occur after immunisation with all vaccines, but historically had been most associated with whole-cell pertussis vaccines in early infancy. There has been a decreased incidence following the change from whole-cell pertussis to acellular pertussis vaccines.

HHE has been observed mainly after the first doses of vaccines at 6 to 8 weeks of age.

In Australia during 2012, 2.2 cases of HHE were reported per 100,000 doses of pertussis-containing vaccine given to children <1 year of age.

Treatment

These episodes self-resolve and often don’t need any treatment. However, the initial management should be for shock and include assessment of airway, breathing and circulation. Careful clinical observation and documentation of the event are vital for differential diagnosis. Urgent medical review is advised for paediatric assessment and to exclude other causes.

Implications and considerations for future vaccines

HHE is not a contraindication to further doses of vaccines, including pertussis containing vaccines.

The recurrence rate for a further HHE is 3.5% [refer to Resources]. No long term sequelae have been identified in the small number of children who have had long term follow-up.

The next scheduled immunisations may need to be given under medical supervision, this can be arranged by contacting the vaccine safety service in your state.

Any adverse event following immunisation (AEFI) in Victoria should be reported to SAEFVIC. Reports can be made online via saefvic.org.au or by telephone on 1300 882 924 (option 1) during business hours.

Resources

Authors: Daniela Say (MVEC Immunisation Fellow) and Teresa Lazzaro (Paediatrician, Immunisation Service, Royal Children’s Hospital Melbourne)

Date: December 2020

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.


Horizon scanning: What's new in vaccines and international immunisation policy?

The MVEC team are often contacted with queries regarding new developments in vaccinology. We try to address this question at our annual Clinical Vaccinology Update.

There are also regular meetings of international National Immunisation Technical Advisory Groups (NiTAGs), whose minutes and PowerPoint slides from their meetings can provide an up-to-date snapshot of vaccinology deliberations [including the United States Advisory Committee on Immunization Practices (ACIP) and the United Kingdom Joint Committee on Vaccination and Immunisation (JCVI)]

.This can help identify:

  • What vaccines are in the pipeline?
  • What are the current topics on the agenda at these NiTAGs?

This snapshot, horizon scanning summary, is undertaken and updated by staff at the National Centre for Immunisation Research and Surveillance (NCIRS), Sydney and can be accessed via the resources below

Resources

Author: Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute)

Reviewed by: Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute)

Date: August 2020

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.


Human papillomavirus (HPV)

What is it?

HPV is a common sexually transmitted infection that can affect both men and women causing cancer of the cervix (in females), other anogenital cancers and certain cancers of the mouth and throat (in both males and females) as well as genital warts (in both males and females). Most HPV infections have no clinical symptoms. This means that people infected with HPV often do not know they have it, and can continue transmitting the virus to others.

How is it transmitted?

HPV is a highly contagious virus that is transmitted through different forms of sexual contact.

Vaccination to prevent infection?

The National HPV Vaccination Program began in 2007 for females, and was extended to include males in 2013. Since 2007, the National HPV Vaccination Program has been credited with dramatically reducing the incidence of the HPV virus in Australia.

Vaccinating against HPV provides highly effective protection against the development of HPV-related cancers and diseases.

The best time to be vaccinated is before a person becomes sexually active.

National HPV Vaccination Program

From January 2018, individuals aged approximately 12 to 14 years will be offered the 9-valent HPV vaccine (Gardasil®9) in a 2-dose schedule (6 -12 months apart) through school based programs.

Gardasil®9 replaces the 4-valent HPV vaccine (Gardasil®), for which a 3-dose schedule has been used.  Gardasil®9 includes the HPV types covered by Gardasil® (6, 11, 16 and 18) plus an additional five oncogenic HPV types (31, 33, 45, 52 and 58).

NB: Immunocompromised individuals require a 3 dose course of Gardasil 9® for protection which should be administered at 0, 2 and 6 months.

Resources

Authors: Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute), Georgie Lewis (SAEFVIC Clinical Manager, Murdoch Children’s Research Institute) and Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute)

Reviewed by: Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute)

Date: July 2020

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.


Hepatitis B

  • Hepatitis B is an infection caused by the hepatitis B virus resulting in jaundice, nausea, vomiting, pain and fever.
  • Disease is transmitted via blood and body fluids of an infected person.
  • Initial hepatitis B infection can often be asymptomatic, meaning a person may be unaware that they are carrying the infection.
  • Following the acute infection, up to 10% of those infected in adulthood, and up to 90% of those infected in infancy will become chronically infected.
  • Chronic infection with hepatitis B virus can lead to end stage liver failure (cirrhosis) and hepatocellular carcinoma.

Prevention of hepatitis B infection

  • Hepatitis B vaccine is currently provided for free on the National Immunisation Program (NIP) at birth (within 7 days), 6-weeks, 4-months and 6-months.
  • A single booster dose is also funded at 12-months of age for those who are born at < 32-weeks gestation and/or < 2000 grams [See MVEC: Preterm Infant Immunisation]
  •  Hepatitis B vaccination is also funded in Victoria for additional at risk groups:
    • Aboriginal and Torres Strait Islander people
    • Household contacts or sexual partners of people living with hepatitis B infection
    • People who inject drugs or are on opioid substitution therapy
    • People living with hepatitis C
    • Men who have sex with men (MSM)
    • People living with HIV
    • Prisoners and remandees
    • People who are no longer in a custodial setting but did not complete the vaccine course while in custody
    • People from endemic countries who arrived in Australia in the last 10 years
  • Certain occupations (including those directly involved in patient care and/or the handling of human tissue, blood or body fluids) also carry an increased risk of exposure to hepatitis B virus. In these instances the vaccine is recommended but not funded on the NIP.

Serological testing

  • Performing hepatitis B serology following hepatitis B vaccination is not routinely indicated.
  • Post vaccination screening, carried out 4-weeks after the final vaccine dose, is recommended for those at significant occupational risk (eg health care workers), those at risk of severe complications of hepatitis B disease (eg immunocompromised, those with pre-existing liver disease), those in whom poor immune response may occur (eg impaired renal function) and sexual partners and household contacts of people living with hepatitis B.
  • If serology is performed more than 8-weeks post the final vaccination dose, results may be considered less reliable.
  • Serology should be performed every 12-months in patients with impaired renal function +/- dialysis regardless of previous serological testing [see Table 1].

Patients with impaired renal function

  • Patients with impaired renal function +/- dialysis are at increased risk of hepatitis B infection. In addition they often have a diminished immune response to the hepatitis B vaccine. The cause of this is not completely understood. It is well documented that the earlier a patient is immunised in the disease progression, the better the response and more long term protection they will have.
  • Impaired renal function is defined as chronic kidney disease (CKD) 4-5 (GFR < 30ml/min)
  • Some patients with impaired renal function may progress to a renal transplant [MVEC: Solid organ transplant recipient]
  • There is evidence to suggest that by vaccinating patients with impaired renal function with a combination hepatitis A and B vaccine (Twinrix® Adult 720/20), seroconversion can be enhanced [see Table 1].
  • If immune response remains sub-optimal following the immunisation recommendations in Table 1, please refer to the below recommendations for management of non-responders to hepatitis B vaccination.

Table 1: Recommended vaccine schedule for those with renal impairment using combined hepatitis A and B vaccine [Twinrix® Adult 720/20]

Age at diagnosis of disease Anti-HBs titre Twinrix® Adult (720/20)# Serology
< 12 months

2 doses (separated by 6 months)

[Commence vaccine course at ≥ 12-months of age]

  • At diagnosis
  • 1 month post 2nd dose of Twinrix® Adult (month 7)
  • Every 12 months thereafter
≥ 12 months If baseline titre at diagnosis is ≥ 10m IU/mL: 2 doses (separated by 6 months)
  • At diagnosis
  • 1 month post 2nd dose of Twinrix® Adult (month 7)
  • Every 12 months thereafter
If baseline titre at diagnosis is < 10m IU/mL: 3 doses (4 weeks between dose 1 and 2; 5 months between doses 2 and 3)
  • At diagnosis
  • 1 month post 2nd dose of Twinrix® Adult (month 2)
  • 1 month post 3rd dose of Twinrix® Adult (month 7)
  • Every 12 months thereafter

# Twinrix® Adult (720/20) is a combination Hepatitis A and B vaccine. It contains 720 ELISA units of HAV antigens and 20mcg of Hepatitis B surface antigen protein. Each dose is 1.0ml given intramuscularly

Non-responders to hepatitis B vaccination

  • A non-responder to hepatitis B vaccination is any person with a documented age-appropriate vaccine history, who has a current Anti-HBs level of <10m lU/mL 4-8 weeks following the final vaccine dose.
  • MVEC recommends the following immunisation pathway for all non-responders: Pathway for routine IM hepatitis B vaccine non-responders
  • Persistant non-responders should be informed of their immune status and advised to minimise exposures.
  • Hepatitis B immunoglobulin may be given to non-immune persons within 72 hours of exposure to prevent infection.

Reference

Authors: Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute) and Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children's Research Institute)

Reviewed by: Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute)

Date: July 2020

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.


HALO

Assessing a person's Health, Age, Lifestyle and Occupation (HALO) can assist in identifying risk factors for vaccine-preventable diseases and therefore determine which immunisations may be warranted in adulthood.

Having certain Health issues, such as asthma; diabetes; heart, lung, spleen or kidney conditions, will pre-dispose people to certain vaccine preventable diseases. Your Age can make you more vulnerable to certain infections. Lifestyle choices, such as overseas travel or smoking are important factors to consider when assessing vaccine recommendations. Your Occupation can result in a greater risk of exposure with diseases, such as for those working in health care.

The HALO is a conversation starter, to help determine which immunisations would be beneficial for you or someone you care for. Remember, it is important to discuss you HALO with your doctor or immunisation provider.

Resources

Author: Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children's Research Institute)

Reviewed by: Rachael McGuire (SAEFVIC Research Nurse, Murdoch Children’s Research Institute)

Date: July 2020

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.