Dear Dr Laura,
I’ve been reading about ‘Aussie flu’. I’m living with HIV, do I need to be worried? Should I be vaccinated?
A very topical question – there has been a lot of news coverage about this type of influenza (flu) as there have been rising reports of cases in the UK. Aussie flu is so-called because it was the driver of a significant flu epidemic in Australia last year. Aussie flu is just one of many strains of flu; there are three main types of flu virus in humans: A, B & C. Winter flu epidemics are caused by A & B whereas subtype C tends to be milder and is not thought to cause epidemics. Type A flu is divided further based on two proteins the virus has on its surface: ‘H’ and ‘N’ antigens. For example, the Aussie flu strain is a subtype A virus and further classified as H3N2 based on those surface proteins. Unlike B, influenza A can infect animals as well as humans; ‘swine flu’ is an example.
A lot of effort goes into monitoring types of flu each year since the following years flu vaccine is based on the commonest strains. Flu mutates constantly; minor genetic changes will alter vaccine effectiveness (which is why they need be updated every year) and mean someone who has already had a particular flu strain (and has developed antibodies against it) can be re-infected with the same type again. Much less commonly there will be a sudden, major genetic change in subtype A virus which means there will be little or no existing immunity and major outbreak (or pandemic) results.
Although flu viruses circulate year round, it is considered seasonal because cases are more common in Autumn and Winter, usually peaking between December and February, which is why it’s considered a seasonal illness and is spread by inhalation of or direct contact with, the virus from people with the infection, mainly through coughing and sneezing. Symptoms start suddenly 1-3 days after being infected and include: sudden fever, generalised aches, extreme tiredness, headache, sore throat, cough, trouble sleeping, loss of appetite, feeling sick, stomach ache, vomiting and diarrhoea. Colds tend to come on more gradually, mainly affect your nose and/or throat and, although you might feel unwell, won’t stop your usual activity (such as going to work!).
The best way to treat flu is rest, keep well hydrated, keep warm and take paracetamol or ibuprofen to help with the symptoms. Be careful with doses since some cold and flu remedies already contain paracetamol – you must not take more than 4 grammes in one day (one paracetamol tablet usually contain 500mg or half a gramme). As flu is a virus antibiotics will not help. Most people will get better by staying at home for a few days and following the previous advice but some people are at higher risk of serious illness. You should go and see your GP if you are still unwell after a week or if you have an underlying medical problem (see NHS Choices). You should seek emergency advice if you develop difficulty breathing, chest pain or cough up blood.
The NHS provides free flu vaccine for people who are at higher risk of complications from flu. Although flu itself can cause serious lung infection people with flu can develop a bacterial pneumonia which is a more common complication. In addition flu can make existing medical problems, such as heart or lung disease, much worse. Having said that the risk of dying from flu is very low – around 1 in 250,000 in healthy people and 1 in 25,000 for people in higher risk groups (i.e. people eligible for vaccine). Groups eligible for free vaccine include: over 65s, pregnant women, people with some types of kidney, liver & heart disease and people with HIV. People working in health and social care can also get vaccine from their employers. The main side effects of the vaccine include pain or swelling at the injection sites and mild flu symptoms for a day or two.
People with HIV are at higher risk of flu complications. The Department of Health and the British HIV Association recommend flu vaccine for all, regardless of CD4, as, although effective HIV treatment reduces the risk of complications the risk is still higher than in the general population. However, a recent study suggested that in high-income countries, HIV was not associated with a higher risk of hospitalisation due to flu. Despite that we should follow guidelines and I think people with HIV should continue to get the flu vaccine.
Public Health England figures show that just under half of the people who are eligible for flu vaccine based on an underlying medical problem have had it – not great uptake! You can get the vaccine from your GP or many local pharmacies. Pharmacies may also provide the vaccine at a cost if you’re not eligible for free vaccine. Most flu vaccines are given by injection and protect against 3 flu strains, two A and one B subtype – this is revised each year and if you are eligible you should have the vaccine every year, ideally before the flu season starts in December. Overall flu vaccine prevents about 60% of infections although this will vary year-to-year depending on how well the vaccine matches the strains that are circulating.
So what else can you do to prevent flu? Flu is very infectious, particularly in the first 5 days of the illness (so avoid unnecessary contact with others), and the virus can live on surfaces like door handles for up to 24 hours. Cough and sneeze into tissues and discard the tissue straight away; regular hand washing with soap and water is important and alcohol-based hand sanitisers will also kill flu.
Dr Laura Waters is an HIV and sexual health consultant at the Mortimer Market clinic and the Boyz Doc. Dr Laura answers your questions every two weeks in Boyz. If you have a question for Dr Laura please email her at firstname.lastname@example.org.