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Vaccine Preventable Diseases

Hepatitis A

What is it?
  • A viral infection that causes the liver to become enlarged, inflamed and tender.
    Severity of disease ranges from a mild illness lasting a few weeks to a severe illness lasting several months.
How is it transmitted?
  • The virus is found in the stools of people infected with the virus
  • Person-to-person
  • Ingestion of contaminated food and water
  • Cold cuts, fruits and fruit juices, vegetables, salads, undercooked shellfish and iced drinks
  • Shellfish and salads are the most frequent sources
What are the symptoms?

Persons infected with the virus may not exhibit any symptoms. If symptoms are present, they may include:

  • Dark urine
  • Fever
  • Tiredness
  • Loss of Appetite
  • Nausea
  • Vomiting
  • Pale Coloured Stool
  • Abdominal discomfort
  • Joint Pain
  • Yellowing of the skin and eyes (jaundice)
Who is at risk?
  • Anyone with no prior exposure or vaccination can contract Hepatitis A
  • Other risk factors for the virus include:
    • Injecting drugs
    • Living in a household with an infected person
    • Travel or work in regions with high rates of Hepatitis A
    • Patients with pre-existing liver disease, eg: patients with Hepatitis B or C are at greater risk of having severe disease

Hepatitis B

What is it?

The most common infection of the liver is caused by the Hepatitis B virus (HBV). It can lead to the following complications:

  • Chronic hepatitis (permanent liver inflammation)
  • Liver cirrhosis (permanent scarring and hardening of the liver)
  • Liver failure
  • Liver cancer
How is it transmitted?

Transmitted through contact with the blood or other body fluids (i.e., semen and vaginal fluid) of an infected person

  • Injecting drug use
  • HBV is a major infectious occupational hazard of health workers (HBV is not spread by contaminated food or water, and cannot be spread casually in the workplace)
What are the symptoms?
  • Acute Symptoms: jaundice, dark coloured urine, abdominal pain, nausea & vomiting
  • Hepatitis B can also cause chronic liver infection that can later develop into cirrhosis of the liver or liver cancer
Who is at risk?

Situations or activities that may carry increased risk for HBV infection for travelers while overseas include the following:

  • Travel to countries with moderate to high rates of Hepatitis B
  • An injury or illness that requires invasive medical attention (eg: injection, IV drip, transfustion, wound stitching)
  • Dental treatment
  • Unprotected sexual contact
  • Sharing illegal drug injection springes • Skin-perforation practices (e.g: tattooing, ear piercing, acupuncture)
  • Cosmetic practices with risk for skin perforation (e.g: Manicure/ Pedicure)
  • Sharing of personal grooming items
    (e.g., earrings, toothbrush, razor)

Seasonal Influenza (Commonly known as “the flu”)

What is it?
  • A viral infection of the respiratory tract
  • At times, the infection can lead to complications or even death10
How is it transmitted?
  • Through respiratory droplets when an infected person coughs, sneezes or speaks
  • The virus can also be spread indirectly when a person touches a surface with flu viruses on it (for example, a door knob) and then touches his or her nose or mouth
What are the symptoms?
  • Influenza typically has a sudden onset with headache, chills and coughs. Followed rapidly by a fever, appetite loss, muscle aches and tiredness.
    Severe cases of influenza can lead to pneumonia and other complications such as bronchitis, sinusitis, ear infection and meningitis (inflammation of the lining that covers the brain)
Who is at risk?
  • The risk for exposure to seasonal influenza during international travel depends on the time of year and destination
  • Older people, young children, people with weakened immune system, or those with heart and lung diseases are at higher risk
  • For protection against influenza, travelers should talk

Do Your Know?

  • Flu is usually a more severe condition than the common cold
  • In Singapore, death rate caused by the flu over the past decade was 14.8 of every 100,000 persons, which is comparable to the death rates in the United States and subtropical Hong Kong

Typhoid Fever

What is it?
  • A life threatening illness, caused by Salmonella Typhi. Serious complications of typhoid fever includes intestinal hemorrhage or perforation, which can be life threatening.
How is it transmitted?
  • Persons with typhoid fever carry the bacteria in their bloodstream
  • The bacterium is usually spread through contaminated food and water
What are the symptoms?
  • Sudden onset of sustained fever, severe headache, nausea, loss of appetite, constipation or sometimes diarrhea
  • In severe cases, mental dullness and meningitis are common
Who is at risk?
  • Risk is greatest for travelers to South Asia (6 to 30 times higher than all other destinations). Other areas of risk includes East and Southeast Asia, Africa, the Caribbean, and Central and South America. The risk of acquiring typhoid fever increases with the duration of stay. However, travelers have also acquired typhoid fever even during visits of less than 1 week.

Do Your Know?

  • An estimated 22 million cases of typhoid fever and 200,000 related deaths occur worldwide each year
  • Almost half (48.5%) of all imported cases are from local residents who contracted typhoid fever whilst travelling in endemic countries

Malaria

What is it?
  • Malaria is a life-threatening mosquitoborne disease • Most malaria cases and deaths occur in sub-Saharan Africa. However, Asia, Latin America, and to a lesser extent, the Middle East and parts of Europe are also affected.
How is it transmitted?
  • Transmitted to humans through the bite of infected mosquitoes
What are the symptoms?
  • The first symptoms – fever, headache, chills and vomiting – may be mild and difficult to recognize as malaria
  • If not treated within 24 hours, malaria can progress to severe illness often leading to death
  • Children in endemic areas with severe disease frequently develop severe anaemia, respiratory distress, or cerebral malaria
  • In adults, multi-organ involvement is also frequent
Who is at risk?
  • International travelers from non-endemic areas are at high risk of malaria because they lack immunity
  • Non-immune/semi-immune pregnant women are also at risk as malaria causes high rates of miscarriage and maternal death. An estimated 200 000 infants die annually as a result of malaria infection during pregnancy
  • People with HIV/AIDS are at increased risk of malaria disease when infected

Meningococcal Disease

What is it?
  • A potentially fatal bacterial infection, known as either meningococcal meningitis (inflammation of the lining surrounding the brain and spinal cord) or meningococcal septicemia (blood poisoning by the meningococcal bacteria).
How is it transmitted?
  • Person-to-person transmission by close contact via droplets of respiratory secretions from the nose and throat of infected persons
  • Up to 5 to 10% of people may be symptomless carriers
What are the symptoms?
  • Intense headache, fever, nausea, vomiting, stiff neck, sensitivity to bright lights, and rashes
  • In young infants, the classic symptoms of fever, headache and neck stiffness may be difficult to detect, and the infant may only appear irritable with poor appetite. As the disease progresses, seizures may occur, irrespective of age
Who is at risk?
  • Persons with compromised immunity, as well as travelers to endemic areas of the world are at increased risk
  • Pilgrims (or large population of people movement) are also at risk. The Haji pilgrimage to Saudi Arabia has been associated with outbreaks of meningococcal disease in returning pilgrims and their contacts

Do Your Know?

  • At any time, 5 to 10% of the population may be carriers of the bacteria that causes meningitis
  • 20% of those who survive the disease will suffer from significant neurological problems including deafness and paralysis15

Yellow Fever

What is it?
  • Yellow fever is a viral disease that occurs in tropical regions of Africa and in parts of South America.
How is it transmitted?
  • Transmitted to human through the bite of infected mosquitoes.
What are the symptoms?
  • Many yellow fever infections are mild, but the disease can cause severe, life threatening illness
  • Symptoms of severe infection are high fever, chills, headache, muscle aches, vomiting, and backache
  • After a brief recovery period, the infection can lead to shock, bleeding, kidney and liver failure. Liver failure causes jaundice (yellowing of the skin and whites of the eyes), which gives yellow fever its name
  • Severe yellow fever infections can be fatal
Who is at risk?
  • Travelers visiting places where yellow fever occurs such as Africa, Central and South Amercia

Tetanus

What is it?
  • An acute, often fatal, disease caused by an exotoxin produced by the bacterium Clostridium tetani.
How is it transmitted?
  • Usually via injuries from contaminated objects • Tetanus has been associated with apparently clean superficial wounds, surgical procedures, insert bites, dental infections, compound fractures, chronic sores and infections, and intravenous drug use
What are the symptoms?
  • Muscle rigidity and painful spasms, often starting in the muscles of the jaw and neck
  • Severe tetanus can lead to respiratory failure and death
Who is at risk?
  • Everyone who has not had a tetanus shot is at risk to this
  • Revaccination is recommended every 10 years

Pertussis

What is it?
  • Pertussis, also known as whooping cough, is a highly contagious acute bacterial disease involving the respiratory tract
  • It is caused by the bacterium Bordetella pertussis
How is it transmitted?
  • Through respiratory droplets when an infected person coughs, sneezes or speaks
What are the symptoms?
  • Typical symptoms include severe cough of several weeks’ duration with a characteristic whoop, often with vomiting, and appearance of blue or purple skin colouration due to low oxygen level
  • In young infants, the cough may be absent
  • Although pertussis can occur at any age, most serious cases and fatalities are observed in early infancy. Major complications include pneumonia, encephalitis and malnutrition (due to repeated vomiting)
Who is at risk?
  • Unprotected young infants are at the highest risk of severe pertussis
  • Older children, adolescents and adults are also at risk if they are not fully immunized

Rabies

What is it?
  • Rabies is a deadly viral infection that is mainly spread by infected animals.
How is it transmitted?
  • Rabies is spread by infected saliva that enters the body through a bite or broken skin. The virus travels from the wound to the brain, where it causes swelling, or inflammation. This inflammation leads to symptoms of the disease. Most rabies deaths occur in children.
What are the symptoms?
  • Symptoms includes: fever, headache, and general weakness or discomfort.
  • As the disease progresses, more specific symptoms appear and may include insomnia, anxiety, confusion, slight or partial paralysis, excitation, hallucinations, agitation, hypersalivation (increase in saliva), difficulty swallowing, and hydrophobia (fear of water).
Who is at risk?
  • Travelling or living in developing countries where rabies is more common, including countries in A frica and Southeast Asia.
  • Activities likely to put you in contact with wild animals that may have rabies, such as exploring caves where bats live or camping without taking precautions to keep wild animals away.