Pandemic flu, also known as pandemic influenza, is a global outbreak that lasts for months. It occurs when a new strain of the flu virus emerges and causes people to get sick worldwide. This new strain is highly infectious and spreads rapidly as humans have little to no immunity for it.
Types
Pandemic flu cannot be predicted and occurs irregularly. From the 19th century to date, there have been several pandemic flus that have come in waves to claim the lives of millions. These are:
- 1889 – 90 flu pandemic or Russian flu – It occurred due to an outbreak of a subtype of the influenza A virus and claimed over 1 million lives out of a population of about 1.5 billion.
- Spanish flu – This pandemic occurred in four successive waves and killed about 20 to 50 million people globally. H1N1 influenza A virus caused this pandemic.
- Asian flu – This is the global pandemic of influenza A virus subtype H2N2 starting from China and killing over 1 to 4 million worldwide during 1957 – 1958. Hongkong flu – The H3N2 strain of influenza A virus was responsible for this deadly pandemic that killed around 1 to 4 million people globally in 1968 and 1969.
- 1977 Russian flu – This outbreak due to an H1N1 flu strain started in the Soviet Union and killed over 0.7 million people.
- 2009 Swine flu was caused by the H1NI/09 subtype of the flu virus that infected over 11 to 21 percent of the entire global population in 2009 – 10.
- Typical seasonal flu – It refers to the annual outbreak of flu during the cold half of the year across the globe and takes about three weeks to reach its peak.
Causes
- Influenza A, B, C, and D are the four types of flu viruses. Of these, influenza types A and B cause seasonal flu that typically occurs every winter.
- Influenza C causes mild infections that are often asymptomatic, while type D virus primarily affects cattle.
- Pandemic flu is mainly caused by influenza type A due to the emergence of newer strains of this highly infectious virus.
- As this strain is so different from the previous strain, few people, if any, have some immunity to it. In turn, it begins to spread rapidly and widely, affecting millions of people across the globe.
- The mixing of a non – human influenza A virus strain, usually from an animal or bird, with a human influenza A virus gives a newer strain that often causes pandemic flu.
Risk factors
- Every pandemic is different, so predicting the high–risk groups before the virus starts spreading is challenging.
- However, almost everyone gets infected by the pandemic flu as it is widespread, and very few people will have any immunity to it.
- Some of the factors that increase the risk of getting pandemic flu are:
- Children younger than five years
- Adults above 65 years
- Pregnant women and women up to two weeks postpartum
- Residents of nursing homes and other long–term care facilities
- Other medical conditions like neurological disorders, heart diseases, weakened immune system, chronic lung disease, etc.
Pandemic flu Signs and symptoms
- Fever (37.8 degrees)
- Cough
- Sore throat
- Runny or stuffy nose
- Body aches
- Muscle aches
- Headaches
- Fatigue
- Vomiting
- Diarrhea
Complications
Pandemic flu is associated with the following health complications:
- Bacterial pneumonia
- Secondary infection
- Massive hemorrhages
- Edema in the lung
- Sepsis
- Multi-organ failure
Diagnosis: How is Pandemic flu Diagnosed?
- The physician examines the symptoms reported by the patient. Testing for the pandemic flu is recommended for a patient who:
- Has an illness that requires hospitalization
- Has a fever that is higher than 37.8 degrees
- Has traveled to a country where the virus is rapidly spreading
- Has been in direct contact with poultry
- Has been in close contact (less than 3 feet) with a person who is suspected or confirmed to have pandemic flu
- Has been in close contact with some who has been hospitalized or died due to the pandemic
- Viral testing – The nasal swab and the throat swab are usually collected and tested to check for the viral strain responsible for the pandemic flu. RT – PCR (Reverse – transcriptase-polymerase chain reaction) is the most frequently employed assay for this purpose.
- Other tests – Depending on the patient’s health condition, doctor may perform additional tests. These include:
- Pulse oximetry
- Chest x-ray
- Complete blood count (CBC) with differential
- Blood culture
- Antibiotic susceptibility testing
- Rapid testing for mycoplasma pneumoniae and Chlamydia species
- Comprehensive metabolic panel (if organ failure is suspected)
Treatment
- Providing relief from the symptoms and restoring overall health is the primary goal of the treatment.
- Medications –
- Antiviral drugs – Oseltamivir, zanamivir, etc. to treat and prevent the spread of the influenza illness. These can also be used for postexposure prophylaxis and used till pandemic – specific vaccines become available.
- Immunization –
- As the viral strain for the pandemic flu and seasonal flu varies, the vaccines used also differ.
- Seasonal flu vaccines do not protect against the pandemic flu. So, newer vaccines are developed for the latter at the earliest.
- People with no immunity get inoculated with two doses of the new vaccine to be fully protected against the virus. It also helps to prevent reinfection during the successive waves of the pandemic flu.
Prevention: How to prevent Pandemic flu?
- Living with it –
- Home quarantine or voluntary isolation till the test results are negative
- Drink plenty of warm fluid
- Healthy diet
- Preventing it –
- Social distancing
- Frequent hand washing
- Wearing masks while going out
- Avoiding hand–to–mouth contact
When to see a doctor? :
Consult immediately with a general physician if there are signs of breathlessness, fever, or sore throat. The cost of antiviral medicines used for the treatment ranges from Rs. 450 to 600.
References:
Is bronchitis contagious?