Typhoid

What is it?

Typhoid and paratyphoid fever are bacterial infections, collectively known as enteric fever and are caused by the bacterias Salmonella enterica subspecies serovars Typhi and Paratyphi A, B and C. Enteric fever is different to the gastroenteritis that can be caused by Salmonella. Symptoms of enteric fever can range from mild to severe, and if left untreated can lead to serious complications or death. Typhoid fever presents more commonly than paratyphoid fever and is associated with higher rates of severe complications and poorer outcomes.

What to look for

Infections caused by typhoid and paratyphoid often present with prolonged fever and fatigue, headache, splenomegaly (enlargement of the spleen), and abdominal symptoms such as pain, lack of appetite, constipation or diarrhoea; often with bacteremia (bacteria in the bloodstream). A rash appearing as small pink clusters on the skin known as ‘rose spots’ can be seen in up to 30% of individuals with enteric fever. In severe cases, complications can include septic shock, gastrointestinal bleeding with perforation, altered conscious state, and death.

How is it transmitted?

Typhoid fever is transmitted via the faecal-oral route and via contaminated food and water sources, most commonly in developing countries with untreated drinking water and poorer sanitation and food handling practices. The incubation period is usually 7-14 days.

Approximately 1 in 20 infected individuals who do not receive treatment for typhoid fever will become an asymptomatic carrier of the disease.

Epidemiology

Whilst not as prevalent in Australia, typhoid fever is a common infective illness in many parts of the world, especially Asia, southeast Asia and sub-Saharan Africa. There were 14.3 million cases of typhoid and paratyphoid fever in 2017, with an estimated global case fatality of 0.95%. Children are disproportionately affected by infection.

Prevention

Prevention of enteric fever includes both vaccination and undertaking food and water precautions whilst travelling in developing countries where typhoid is endemic. There is no specific vaccine for paratyphoid fever however there is some evidence to suggest that administration of the oral typhoid fever vaccine can provide some cross protection against paratyphoid fever.

Vaccines

There are 3 vaccines available in Australia for protection against typhoid fever:

VaccineAgePlatformAntigenRouteVolumePrimary courseBooster
Typhim Vi®≥ 2 yearsInactivatedTyphoidIM0.5ml1 doseDue in 3 years
Vivaxim®§≥ 16 yearsInactivatedTyphoid/hepatitis AIM1.0ml2 doses, 6 months apartTyphoid only due in 3 years
Vivotif®*≥ 6 yearsLive-attenuated^TyphoidOral1 capsule3 doses (day 1, 3 & 5) 3-dose primary course- booster dose required after 3 years
4 doses (day 1, 3, 5 & 7)4-dose primary course- booster dose required after 4 years

§Whilst not registered for use in this age group, a number of travel medicine practitioners routinely administer Vivaxim® to children aged 2-15 years. Refer to Lau C. et al The tolerability of a combined hepatitis A and typhoid vaccine in children aged 2-16 years: an observational study Journal of Travel Medicine 2016: 15, 23 (2) for more information.
*If a patient is taking both Vivotif® oral and the oral cholera vaccine (Dukoral®), these should be administered 8 hours apart due to the risk of components of the cholera vaccine impacting how the typhoid vaccine is absorbed in the gut.
^Not to be given to people who are immunocompromised, taking immunosuppressive medications, pregnant women, or those taking oral antibiotics.

Other precautions

In addition to vaccination, travellers should also maintain the following precautions to limit exposure to infections:

  • undertaking effective hand washing practices
  • drinking bottled or boiled water
  • avoiding high-risk foods and drinks including:
    • raw (or undercooked) shellfish
    • cold meats
    • salads
    • untreated water and ice in drinks.

Resources

Authors: Rachael Purcell (RCH Immunisation Fellow), Francesca Machingaifa (MVEC Education Nurse Coordinator) and Rachael McGuire (MVEC Education Nurse Coordinator)

Date: July 8, 2022

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.


Thrombosis with thrombocytopenia syndrome (TTS)

Thrombosis with thrombocytopenia syndrome (TTS), also known as Vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) or vaccine-induced immune thrombotic thrombocytopenia (VITT), is a rare and newly identified syndrome which has been reported in people who have received adenoviral vector COVID-19 vaccines such as Vaxzevria (AstraZeneca) and the Johnson & Johnson/Janssen COVID-19 vaccine.

What is TTS?

The syndrome is characterised by thrombosis formation (blood clots) combined with thrombocytopenia (low platelet count).

TTS can be classified into 2 tiers based on the location of thrombosis and severity of symptoms. Cases are further classified based on if there has been recent exposure to heparin or not.

Tier 1:

  • uncommon site of thrombosis (eg brain – cerebral venous sinus thrombosis [CVST] or gut – eg. splanchnic vein, associated with bowel ischaemia and surgery, portal vein or other rare venous and arterial thromboses)
  • may also concurrently have thrombosis in more common locations (e.g deep vein thrombosis or pulmonary embolism)
  • platelet count < 150,000 per microliter
  • positive (+) heparin-P4 ELISA HIT antibody result is supportive, but not required for diagnosis

Tier 2:

  • common sites of thrombosis such as leg or lungs (eg. venous thromboembolism, deep vein thrombosis, pulmonary embolism)
  • platelet count < 150,000 per microliter
  • positive (+) heparin-P4 ELISA HIT antibody result is required

Tier 1 tends to be associated with more severe presentations, and carries a higher risk of morbidity and mortality than Tier 2. Evidence is emerging that Tier 1 is more common in younger age groups.

How do adenoviral vector vaccines trigger TTS?

The exact mechanism of how TTS is triggered is still under investigation, however the majority of cases are associated with the finding of anti-PF4 antibodies. Currently there are no clear diagnostic markers to indicate who is at risk of this syndrome.

TTS appears similar to an autoimmune condition known as heparin induced thrombocytopenia (HIT), where an immune reaction to the medication heparin impacts platelet function, leading to thrombosis.

What is the risk of TTS?

Current Australian data estimates that the risk of developing TTS after dose 1 of Vaxzevria is approximately 2.4 per 100,000 persons in those <60 years; and 1.8 per 100,000 persons above 60 years.

The risk of developing TTS following dose 2 occurs at a much lower rate; however global experience and data following dose 2 is still emerging.

Is there a risk of developing other clotting disorders after receiving adenoviral vector vaccines?

There is currently no evidence that adenoviral vector vaccines increase the overall risk of developing other standalone thromboses (eg. other clotting disorders leading to deep vein thromboses, pulmonary emboli, myocardial infarction, stroke) beyond the baseline rate in the general population.

TTS is different to other commonly diagnosed thromboses as it is triggered by an immune response to a specific type of vaccine which then results in the combination of both thrombosis (clots) and thrombocytopenia (low platelet count).

Who is at risk of TTS?

Currently there are no clear diagnostic markers to indicate who is at increased risk of TTS. Emerging evidence indicates there to be a higher risk of TTS in younger individuals (< 60 years old), although there has been a number of cases identified in older adults. There is some evidence to suggest that the incidence is higher in women compared to men, although this may be because more vaccine doses have been given to women in vaccine rollouts worldwide thus far.

Are there medical conditions that increase the likelihood of developing TTS?

There is currently no evidence or biological risk factors that have been identified that either increase or decrease your risk of TTS.

There is currently no evidence to suggest that there is an increased risk of developing TTS in people with the following conditions:

  • history of blood clots in typical sites
  • increased clotting tendency that is not immune mediated
  • family history of blood clots
  • history of ischaemic heart disease or stroke
  • current or past thrombocytopenia (low platelet count)
  • those receiving anticoagulation therapy.

Vaccine recommendations

As a precautionary measure, mRNA vaccines (Comirnaty and Spikevax) are recommended by ATAGI as the preferred COVID-19 vaccine for people aged < 60 years due to the increased risk of developing TTS.  ATAGI also recommend that people with a past history of idiopathic splanchnic vein thrombosis, antiphospholipid syndrome with thrombosis, CVST or HIT should preferentially receive an alternate COVID-19 vaccine.

What are the potential symptoms of TTS?

Individuals with TTS generally present with the following symptoms in the 4-42 days after vaccination with an adenoviral vector vaccine:

  • cerebral venous thrombosis: persistent headaches, visual changes, focal neurological symptoms (e.g. movement or sensation changes), seizures, coma, confusion
  • splanchnic vein thrombosis: abdominal pain
  • pulmonary embolus: chest pain, shortness of breath
  • deep vein thrombosis: leg pain, redness or swelling
  • arterial ischaemia: changes to limb (pallor and coldness), symptoms of heart attack (e.g. chest pain, shortness of breath)
  • thrombocytopenia: pinpoint bruising or rashes, bleeding or bruising

NB: These symptoms are different from the common or expected side effects following vaccination which usually occur in the first 24-48 hours and last 1-2 days.

What are the outcomes of developing TTS?

TTS can cause serious long-term disability or death if not recognised and treated in a timely fashion. If TTS is suspected, there is likely to be an investigation of platelet levels, other bloods including D-dimer, clotting factors and special immunological and antibody tests, as well as imaging studies to determine the site and size of any potential thrombosis/clots. If warranted, decisions for specific treatments for this condition are to be made in consultation with a specialist haematologist and may include anticoagulation with a non-heparin anticoagulant and/or intravenous immunoglobulin (IVIG).

Authors: Daryl Cheng (Paediatricican, Royal Children’s Hospital), Francesca Machingaifa (MVEC Education Nurse Coordinator), Davina Buntsma (MVEC Immunisation Fellow) and Rachael McGuire (MVEC Education Nurse Coordinator)

Reviewed by: Linny Kimly Phuong (Immunisation Consultant, SAEFVIC)

Date:  25 October 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.


Tetanus prone wounds management

What is tetanus?

Tetanus is a bacterial infection caused by the bacteria Clostridium Tetani. It commonly lives in dirt, dust and animal waste and the spores are usually introduced into the body via lacerations or puncture wounds. The spores can survive in a wound for as long as 3 months before becoming active. The most common time frame for presentation of tetanus is around 14 days, but it can also be delayed (up to months), after the injury. Unlike other vaccine preventable diseases, tetanus is not transmissible from person to person.

Examples of wounds that are considered tetanus prone-

  • Bites, either animal or human
  • Deep penetrating wounds
  • Wounds with foreign bodies i.e. splinters
  • Burns
  • Open fractures
  • Cuts or lacerations with outdoor equipment
  • Tooth reimplantation post avulsion
  • IV drug use sites

Tetanus can occur following trivial or even unnoticed wounds. Tetanus prophylaxis should be strongly considered for all unimmunised or partially immunised persons, regardless of the nature of the wound.

Signs and Symptoms

People infected with tetanus commonly show signs of muscle spasm, mainly around the face and neck, including lock jaw. Spasms can last for significant amounts of time, requiring large amounts of analgesia.

Severe cases can lead to breathing difficulties, respiratory infections and heart attack. 1 in 10 people with tetanus will die despite receiving prompt medical treatment.

Prevention

Vaccination is the most effective way to prevent tetanus.

As per the National Immunisation Program (NIP), a primary course of tetanus vaccination is given at 6-weeks, 4-months, and 6-months of age (Infanrix hexa®).

Boosters are then scheduled at-

  • 18-months (Infanrix®/Tripacel®)
  • 4-years (Infanrix-IPV®/Quadracel®)
  • Year 7 (high school program)/12 to 13-years of age (Boostrix®)

A further booster dose as dTpa (Boostrix®/Adacel®) is recommended but not funded, for adults aged ≥ 50-years who have not received a dose of tetanus-containing vaccine in the last 10 years.

Regular booster doses every 10-years are no longer recommended. However immunisation advice regarding the management of a tetanus prone wound varies from this [see below].

Tetanus prone wounds

The correct management of a tetanus prone wound is vital in the prevention of tetanus [see resources: RCH Clinical Practice Guideline].

Key messages include:

  • Where applicable, wounds should be cleaned, disinfected, and surgically treated if required
  • In paediatric patients, a full immunisation history should be taken, ensuring that a primary course of tetanus vaccination has been completed
  • If a patient is > 5 years post a tetanus vaccine, then a booster is recommended
  • An important age group to consider for a booster are those aged between 9-13 yrs, as they are 5-years post their 4-year old vaccine, and may not have yet received their Year 7 (adolescent) booster

Children or adults who are unimmunised or only partially

Every person will receive an injury at some point in their life. Whether it is tetanus prone, will depend on medical assessment. Even the most superficial wounds could be at risk of tetanus depending on the mechanism of injury.

An unimmunised or partially immunised person is at greatest risk of contracting tetanus. The elderly population are often included in this group due to timing of their last booster, most commonly being exposed whilst gardening.

A partially immunised person is one who has not yet completed a primary course, or has received < 3 doses of a tetanus containing vaccine. These people require not only a tetanus-containing vaccine but also tetanus immunoglobulin (TIG) [refer to resources for specific advice].

If immunisation history is in doubt, TIG and a tetanus-containing vaccine should be administered.

Immunoglobulin provides protection for up to 1 month after administration. Vaccination provides protection against the toxin and not the bacteria. A full course of 3 doses of a tetanus-containing vaccine should be completed to ensure ongoing immunity. If individual advice is required consider a referral to a Specialist Immunisation Clinic.

ADT® vaccine

The use of ADT® in children aged < 10-years is not recommended as it does not contain enough antigen to promote an adequate immune response in the unimmunised, however there are unlikely to be safety issues. Parents requesting this option should be made aware of the increased risk of contracting tetanus.

Management of immunosuppressed patients with a tetanus prone-wound

Immunosuppressive medications are becoming more common place in the management of particular medical conditions. Patients who may be immunosuppressed include:

  • Autoimmune conditions ie: IBD, lupus, rheumatologocial conditions
  • Solid organ transplant recipients, Haematopoietic stem cell transplant recipients
  • All oncology patients

Patients who are immunosuppressed should be considered unimmunised and treated accordingly with immunoglobulin and a vaccine.

Resources

Author: Lynne Addlem (Immunisation Nurse, The Royal Children’s Hospital) and Rachael McGuire (Education Nurse Coordinator)

Reviewed by: Lynne Addlem (Immunisation Nurse, The Royal Children’s Hospital)

Date: September 2020

Materials in this section are updated as new information becomes available. The Melbourne Vaccine Education Centre (MVEC) staff regularly review 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.


Travel medicine

Travel medicine focuses on disease prevention and injury risk minimisation with advice based upon the travelling person’s individual circumstances such as the location and purpose of travel, duration and time of year, as well as any underlying medical conditions or other risk factors.

Where to get travel advice

General Practitioners and travel medicine clinics can provide recommendations for preventative care and offer vaccination. There are also paediatricians who specialise in infectious diseases or immunisation who can provide advice for children (and their families). There are also a number of excellent websites that can be accessed to obtain country specific updates and information on emerging infections [see Resources below].

When to seek advice

For specific pre-travel advice, consultation with a health care professional is best done a minimum of 4-6 weeks prior to departure, which allows time to develop immunity following any recommended vaccines prior to arrival at the travel destination. Depending on which vaccines are recommended, a course of vaccines over time may be indicated before a person is considered fully protected.

As most travel specialists require a GP referral and may have wait times for an appointment, it is important to factor this into travel planning timelines.

Vaccines

Some routine vaccines can be given earlier than scheduled or as additional doses for the purposes of travel. Examples of this include:

  • MMR (measles, mumps and rubella) vaccine: an extra, funded dose can be administered between the age of 6-11 months if travelling to an area where measles are endemic
  • Meningococcal vaccines:
    • MenACWY (Nimenrix) vaccines can be administered from 6 weeks of age in order to provide earlier protection (scheduled on the NIP at 12 months of age and in year 10 of secondary school)
    • Meningococcal B (Bexsero) vaccines can also be given from 6 weeks of age (not funded on the National Immunisation Program (NIP) for all, but can be purchased privately for those who do not qualify for a funded dose)
  • Influenza vaccine: depending on the time of year and destination of travel, it may be advisable to receive an influenza vaccine
  • COVID-19 vaccines: due to ongoing emerging strains of COVID-19 disease, it is important to ensure a primary course of COVID-19 vaccination is complete along with any recommended boosters based on current recommendations.

Other travel-related vaccines, depending on your location and duration of travel might include:

Other precautions

Other preparations for travel may include:

  • considering the need for malaria prophylaxis (medication to prevent malaria)
  • measures to prevent mosquito-borne disease such as wearing long-sleeved clothing, mosquito nets, and insect repellent than contains DEET
  • food and water safety.

Immunocompromised and pregnant travellers

Individuals who are immunocompromised as a result of a medical condition or specific therapies are encouraged to seek travel advice early to maximise protection against vaccine preventable diseases prior to travel.

Similarly, women who are planning pregnancy or who are pregnant, should seek travel advice as early as possible to ensure optimum protection for both the mother and unborn baby. Women planning pregnancy with a high likelihood of travel, should consider vaccination prior to pregnancy noting that live-attenuated vaccines are contraindicated during pregnancy.

Visiting friends and relatives (VFR)

VFR travel is one of the most common reasons for international travel. A VFR traveller is an immigrant who travels from the high-income country they are living in to their lower-income country of birth to visit friends or relatives. A travel consult prior to VFR travel should consider whether an individual has had routine NIP vaccines or a history of vaccine preventable disease/s as well as vaccines indicated for the country they are travelling to. Rates of some travel-related infections are higher in this population and taking appropriate precautions such as vaccination and considering food and water safety is important in ensuring optimum protection.

Resources

MVEC travel related resources

The RCH travel health resources

Yellow Fever vaccination centres

The CDC in the United States

Other resources

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

Reviewed by: Rachael Purcell (RCH Immunisation Fellow), Francesca Machingaifa (MVEC Education Nurse Coordinator) and Rachael McGuire (MVEC Education Nurse Coordinator)

Date: July 12, 2022

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.