Dr Jason Naicker tells us why the inactivated flu vaccine is best for most cancer patients.
The flu vs. a common cold
Influenza (flu) and the common cold are both respiratory illnesses. But they are caused by different viruses. Yet have similar symptoms.
In general, flu is worse and symptoms are more intense. People with colds are more likely to have a runny or stuffy nose. And, colds generally don’t result in serious health problems, such as pneumonia or hospitalisations.
According to the South African National Department of Health, influenza kills between 6 000 – 11 000 South Africans every year. More than half are the elderly and HIV positive people.
More than 25% of people hospitalised for pneumonia, and about 14% of patients hospitalised for flu-like symptoms, will test positive for influenza.
Patients with chronic diseases, such as diabetes, kidney failure, cancer, and cardiac failure, are at increased risk of being hospitalised with flu.
In SA, flu is seasonal and circulates predominantly in the winter months. ‘Flu season’ typically begins in June, though it could start earlier or later.
The National Health Laboratory Service publishes weekly website updates on influenza virus activity, should you require more information.
How does the influenza virus spread?
The influenza virus is usually spread from person to person by droplets, when a person with flu speaks, coughs or sneezes, and these droplets land in the mouths, noses or eyes of people close by.
It can also be transmitted when people touch objects that have the flu virus on and they touch their mouth or nose.
The time for the onset of symptoms usually is four days. This may include fever, cough, headaches, sore throat, body aches, diarrhoea and vomiting.
Should cancer patients get the flu vaccine?
When undergoing cancer treatments, prevention of infection is of paramount importance, especially with an impaired immune system. Infections in cancer patients often carry excessive morbidity and mortality, and antimicrobial therapy is usually less effective.
Immunisation through vaccination seems like the logical way to prevent infection. But, many patients with impaired immunity may not be able to mount a proper immune response to active vaccinations.
Although some vaccines provide some benefit to the immunocompromised individual, a vaccine response can’t be guaranteed.
Successful protection in these patients may require vaccines, passive immunisations (e.g. immune globulins), and anti-viral prophylaxis.
Live vaccine vs. inactivated vaccine
In adults with cancer, those with haematologic (blood) cancers are more at risk of being immunocompromised than those with solid tumours.
However, patients with solid tumours are also at risk of infections based on debility, malnutrition, etc.
Vaccines shouldn’t be given at times of immunosuppression because they may be ineffective, and, if it’s a live vaccine, it may result in vaccine-derived infections.
A live vaccine uses a weakened form of the virus (measles, mumps, rubella), while an inactivated vaccine uses certain parts or proteins from the virus to create immunity.
In South Africa, the inactivated vaccine is the only type available. It contains three types of inactivated flu viruses, as per the WHO recommendations for a flu season
Inactivated vaccine for cancer patients
Adults with cancer should receive this inactivated influenza vaccine every year. The exceptions are patients undergoing treatment with anti-B cell antibodies (e.g. rituximab), since their immune responses will be poor. Such patients should have the vaccination delayed for at least six months until after treatment.
It’s also recommended that patients receiving intensive chemotherapy be given the inactivated influenza vaccine. Family members of patients undergoing active cancer treatments should also be vaccinated.
Anti-viral prophylaxis may be considered in unvaccinated patients who have been exposed to the virus. This should be discussed with your treating doctor. A good example that may be prescribed is oseltamivir (Tamiflu).
Effectiveness of vaccine
On average, the flu vaccine affords about 60% effectiveness in adults. It doesn’t, however, protect against other viruses that may cause colds in the winter season.
Always advise your doctor if you are not feeling well while on cancer treatments. Early diagnosis and treatment of infections improves outcomes drastically and minimises your downtime.
MEET OUR EXPERT – JASON NAICKER
Dr Jason Naicker is a consultant medical oncologist at Rosebank Hospital. He served as medical advisor at Janssen Cilag, covering oncology and anti-infectives.