diphtheria

Diphtheria

Parents & Caregivers
Introduction: 

Diphtheria is a rare but serious infectious disease. The bacteria usually causes infection of the throat and nose but can also cause skin infections. While some cases may be mild, the bacteria can produce dangerous toxins that cause severe complications which can be life-threatening. Such complications include heart trouble, paralysis, and kidney failure. Cases of diphtheria in New Zealand have declined significantly over the last century with very few cases reported in the last 50 years.

A brief history: 

Diphtheria used to be common in New Zealand, with a total of 794 deaths in the five years from 1917 to 1921. Fortunately, in part because of vaccination, diphtheria has disappeared from New Zealand. However, it is common in other parts of the world and is, therefore, only a plane ride away.

The current New Zealand situation: 

Since 1979, there have only been 4 confirmed diphtheria cases in New Zealand. These isolated cases occurred in 1987, 1998, 2002 and 2009.

It is believed that diphtheria vaccine protection wanes over time which is why the vaccine has been introduced into adult schedules in New Zealand.  Diphtheria vaccine is included in the childhood immunisation schedule in New Zealand and remains an essential component of child vaccine programmes worldwide.

Symptoms: 
  • Inflammation of the upper respiratory tract including the nose and throat. This may include sore throat, breathing problems, bloody or watery drainage from the nose, hoarseness, a bark-like cough, and painful swallowing.
  • Some cases will experience infection of the skin.  This may include skin lesions.
  • However,some cases may not experience any symptoms.
How do you get it?: 

Diphtheria is spread through close personal contact with someone who is infected or is a carrier of the bacteria who shows no symptoms. Spread commonly occurs through way of respiratory droplets (originating from a cough or a sneeze). The bacteria can also spread through contaminated objects or food.

What are the risks?: 

The effects of diphtheria can range from mild to severe.
•For those infected, there is the potential for the diphtheria bacteria to release harmful toxins which can spread through the blood stream and affect major organs.
•Diphtheria toxin can cause significant damage to the heart, nerves, and kidneys.
•Diphtheria can be fatal. 5-10% of those infected die, even with treatment.

Who is most at risk?: 
  • Those who are not immunised are at the greatest risk.
  • Crowded environments and poor hygiene are known to increase risk for diphtheria.
  • The majority of cases are reported in children under 10 years of age.
Treating the symptoms: 

People suspected of having diphtheria will be given an antitoxin in a jab to the muscle or into the vein. Infection is then treated with antibiotics, such as erythromycin or benzathine penicillin. Additional treatment may include intravenous fluids, oxygen, bed rest, heart monitoring, use of a breathing tube, and correction of any blocked airways.

Preventing Disease Spread: 
  • The person with diphtheria is excluded from school until they have recovered and had two negative throat swabs.
  • Contacts of the person with diphtheria are given antibiotics and may also need to have a booster vaccination with a diphtheria-toxoid containing vaccine
  • Contacts who are children are excluded from early childhood education, daycare, school and community activities until throat swabs shown they do not have the disease.
  • Adults who work with food or children are excluded from their work until throat swabs shown they do not have the disease.
Health Professionals
Causative organism: 

Diphtheria is caused by the bacteria Corynebacterium diphtheriae. The toxin produced by some diphtheria bacteria can cause serious and life-threatening infections.

Clinical signs, symptoms and complications: 

  • Membranous inflammation of the upper respiratory tract and nasopharynx, which may cause hoarseness, loss of voice or stridor (greyish membrane with a characteristic mousy smell). This may be accompanied by mildly painful tonsillitis or pharyngitis (90%).
  • Lymphadenopathy may lead to a “bull neck” appearance and the angle of the jaw may be obliterated. Unilateral or bilateral paralysis of the palatal muscles may lead to dysphagia
  • Skin and mucous membrane (mouth, vagina) lesions may occur in less serious disease. Pain, tenderness, and erythema at the site of infection progresses to ulceration with sharply defined borders and formation of a brownish grey membrane.
  • Infection by toxigenic strains may lead to toxin release, which can cause myocarditis, peripheral neuropathy with flaccid paralysis, renal failure secondary to tubular necrosis, stupor, coma and death.
  • 10% of patients die of mechanical airway obstruction or circulatory collapse.
Method of transmission: 

Humans are the only known reservoir of diphtheria. The discharge from an infected person’s nose, throat, eye and skin lesions contains the bacteria and is contagious.

  • Transmission mostly happens from intimate contact with an infected person although fomites and food-borne sources can serve as vehicles of transmission.
Public health significance: 

Diphtheria is rare in industrialised countries where immunisation programmes have run for decades. However, it's still common in some countries.

  • Since 1990, epidemic diphtheria has re-occurred through the Newly Independent States (NIS) of the former Soviet Union, including Russia, the Ukraine and the central Asian republics. In the 6 years from 1990 through 1995, the NIS accounted for more than 90% of all diphtheria cases reported to the World Health Organization from the entire world.
  • Illness is most common in low socio-economic groups living in crowded conditions. Infection can occur in immunised and partially immunised people, but disease is most severe in people who are not immunised.
  • Antibiotic treatment usually renders patients non-infectious within 24 hours.
  • An estimated 20% of those under 20 and 75% of those over 65 worldwide are thought to have insufficient immunity to diphtheria due to inadequate immunisation coverage and waning immunity.
  • While immunisation leads to the disappearance of toxigenic strains, non-toxigenic strains may become toxigenic through phage transmission. This makes the possibility of a resurgent diphtheria epidemic a real threat wherever there is insufficient community (herd) immunity.
New Zealand epidemiology: 

Between 1917 and 1921 there were 794 reported deaths in non-Māori from diphtheria. Regular epidemics of infection occurred in New Zealand until 1950, and further outbreaks occurred in Milton and the Waikato in the 1960s.

In 1998 the first case of diphtheria was reported in New Zealand since 1979, and this was the first toxigenic isolate since 1987. In 2002 a four-year-old child was reported after a toxigenic strain was isolated from a hip aspirate. The child had no toxin related symptoms and had been fully vaccinated for age; this would not be regarded as a vaccine failure. In 2009 two cases of toxigenic diphtheria were isolted, the index case had acquired a tattoo in Samoa and the second case was a a household member ot the index case. There is no current data on the proportion of New Zealand adults susceptible to diphtheria.

The 1985 National Serum Survey found that 73 percent of five year olds, 65 percent of 10 year olds and 53 percent of 15 year olds had protective levels of diphtheria antibody. The decline apparent with age suggests that there is likely to be a large and increasing pool of adults susceptible to diphtheria in New Zealand. This was the reason for the introduction of adult tetanus diphtheria (Td) vaccination in 1994 and for the addition of adult tetanus/diphtheria boosters at 45 and 65 years in 2002.

Prevention: 
  • People with diphtheria should be excluded from school until recovery and had two negative throat swabs.
  • Local health officials should be notified when cases of diphtheria occur. Public health measures include isolation of the contagious person and contact tracing to identify additional people who may be infected or at risk of infection.
  • Pharyngeal culture and prophylactic erythromycin or benzathine penicillin for close contacts.
  • Child contacts of the contagious person should be excluded from school, early childhood services and community gatherings until they are known to be culture negative.
  • Adult contacts who are food handlers or who work with children should be excluded from work until known to be culture negative.

Immunisation remains the only well-established mode of disease prevention. Diphtheria vaccination has been widely offered since World War II, leading to virtual disappearance of the disease in many countries.

  • Active immunisation against diphtheria is recommended during convalescence because having the disease does not necessarily convey immunity.
  • Fully immunised children aged up to and including six years, who are contacts of the contagious person, and who have only received three doses of diphtheria toxoid-containing vaccine within the last five years: give one injection of DTaP-IPV.
  • Fully immunised contacts aged seven years and older who have not received a booster dose of a diphtheria toxoid-containing vaccine within the last five years: if aged 7–15 years, give one injection of Tdap; if aged over 15 years, give one injection of Td or Tdap, the latter is not funded.
Treatment: 

Diphtheria antitoxin is injected daily for 14 days for respiratory diphtheria. Sensitivity testing (skin or eye testing) should be conducted as only diphtheria antitoxin of equine origin is available.

Benzathine penicillin or erythromycin is used to eliminate the bacteria, reduce toxin production and decrease infectivity. Intravenous antibiotics are used until the person is able to swallow oral antibiotics comfortably. The use of antibiotics is in addition to daily antitoxin injections.

Additional treatment may include intravenous fluids, oxygen, bed rest, heart monitoring, use of a breathing tube, and correction of any blocked airways.

Disease Effects vs Vaccine Side Effects (Table)
Disease Description: 

Diphtheria is a rare but serious bacterial illness that usually causes infection of the throat and nose but can also cause skin infections.

Effects of disease: 
Throat swelling and difficulty breathing.
Sinusitis, otitis media (ear infection),pneumonia.
Heart muscle inflammation and failure.
Kidney damage and failure.
15-20% of cases develop delayed nerve complications e.g. peripheral neuritis.
5-10% of those infected die, even with treatment.
Common side effects of vaccine: 
Soreness/pain, redness and/or swelling around the injection site.
Fever over 38°C.
Decreased appetite, vomiting and/or diarrhoea.
Irritability, restlessness.
Unusual crying.
Fatigue.
Uncommon side effects of vaccine: 
Fever over 39°C.
Muscle or joint stiffness or pain.
Redness and/or swelling more than 6 cm in size around the injection site. In a small percentage of vaccine recipients the reactions will be severe enough to limit movement of the arm and may last for about a week.
Swelling involving the entire thigh or upper arm occurs in 2–3 percent of children after administration of the fourth and fifth doses of acellular pertussis vaccine. It resolves spontaneously without long term consequences.
Rare/very rare side effects of vaccine: 
Anaphylaxis.
Urticaria.
Idiopathic thrombocytopenic purpura.
Persistent (> 3 hours) inconsolable screaming.
Hypotonic, hyporesponsive episode (HHE) with 24 hours of immunisation.
Convulsion within 2 days of immunisation.
High fever over 40°C.
Extensive swelling or weakness of the vaccinated limb.
Inflammation of the nerve in the arm causing muscle weakness and pain (brachial neuritis) occurs within four weeks of immunisation, 1- 2 times per 200,000 doses.
Encephalopathy less than once in one million doses.

ADT™ Booster

Td

ADT™ Booster is used for primary and booster vaccination of children 7 years of age and over and adults to protect against tetanus and diphtheria. An alternative vaccine called Boostrix®, which protects against tetanus, diphtheria and pertussis (whooping cough), can be substituted for one, two or all three doses of the primary vaccinations in these age groups. Both ADT™ Booster and Boostrix® are licensed as booster vaccines. They are used for primary vaccination out of licensure as there is no alternative primary vaccination strength vaccine available in New Zealand for these age groups. When the vaccine is used for a primary vaccination course, use will be outside of current licensure. No safety concerns are expected with use in these circumstances.

Infanrix®-IPV

DTaP-IPV

Infanrix®-IPV is used for primary and booster vaccination of infants and children to protect against diphtheria, tetanus, pertussis and poliomyelitis. Infanrix®-IPV can also be used for catch-up immunisation for children up to their 10th birthday.

Infanrix®-hexa

DTaP-IPV-HepB/Hib

Infanrix®-hexa is used for primary and booster vaccination of infants and children to protect against diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and disease caused by Haemophilus influenzae type b. Infanrix®-hexa can also be used for catch-up immunisation for children up to their 10th birthday.

 

Boostrix®

Tdap

Boostrix® is used for booster vaccination of adolescents aged 11 years and pregnant women between 28-38 weeks gestation* to protect against diphtheria, tetanus and pertussis (whooping cough). Boostrix® can also be used for catch-up immunisation for children aged 7 years# to under 18 years.

*After immunisation protection against pertussis takes up to two weeks to develop. Whilst immunisation between 38-40 weeks gestation is still safe for mother and baby later immunisation means the newborn may still be exposed to the disease by their mother on delivery and/or during the first two weeks of life. The PHARMAC decision to limit funded Boostrix® to 28-38 weeks gestation maximises the benefit of immunisation against pertussis whilst being accountable for the use of public funds. Pregnant women can choose to purchase Boostrix® privately after 38 weeks gestation or at any time after delivery.

#Although Boostrix® is not licensed for use in children aged 7 years to under 10 years it has been used in New Zealand and overseas in this age group and there are no safety concerns with off-label use.

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