The “common cold” is common. Most of us will have at least one or two per year. Children get sick more often and very young children often get more than five colds per year.

Even though it’s so common there’s a lack of good research looking into this infection and ways to prevent and treat it.

What is a ‘cold’?

The common cold is caused by viruses. It’s generally an acute self-limiting infection, which means it comes on quickly and resolves by itself. It involves our upper respiratory tract and airways (nose, throat, pharynx and larynx).

The incubation period after picking up the virus is usually about two days before our symptoms start. The illness then often lasts for five to 10 days.

You are likely to be contagious while you have symptoms but you’re most contagious in the early part of illness (the first few days). Once your body effectively fights the infection, the numbers of the virus in your body will drop off and you will recover. We recover from these viral infections when we develop immunity to the strain infecting us by sending white cells to kill the virus and making antibodies active against it.

Sore throat, malaise, cough, sneezing and running noses are the more common symptoms. Headaches, fevers, body aches and severe tiredness are relatively less common.

Some of its signs and symptoms can overlap with other conditions such as hayfever, although the latter is usually without a sore throat.

How do we catch colds?

It was, and is still thought by many, that exposure to cold temperatures, especially in winter caused the common cold. By itself this does not appear to be true. The common cold is caused by viruses. One needs to catch one of these viruses to get a cold – just exposure to low temperatures won’t do it.

However when it’s cold and wet outside we are more likely to be indoors and be in more crowded places including with other people who may have a cold. Hence cold weather does make it more likely that we will catch a cold, especially if we are near people who have one.

Its common association with winter and cold weather likely contributed to its name. Whether cold weather and lowered humidity also contribute to the transmission of these viruses is still unclear.

We often believe most of us get these types of respiratory infections because we breathe in the viruses that cause them. The viruses are present in aerosols and droplets so when people cough and sneeze, we can inhale them. However what now looks more likely, is that most of us get these infections via our hands.

We often touch contaminated surfaces. Then we infect ourselves when our hands touch our mouth, nose and/or eyes. So it’s by our hands that we most often “catch” a cold. This is also why good hygiene, along with regular hand-washing with soap and water or with alcohol-based solutions not only decreases our chances of catching a cold but helps protect those around us as well.

What causes colds?

The common cold is caused by quite a few different viruses – not just one. Rhinoviruses are the most common cause. These are small RNA viruses named after the nose “rhino” and which grow best at temperatures found in the nose 33-35°C.

Other common causes are coronaviruses (RNA viruses that under a microscope look to have a crown or halo) and influenza viruses. A host of other viruses including RSV, parainfluenza virus, metapneumovirus and adenovirus are some of the other causes.

All the viruses cause the same type of symptoms. Therefore you can’t tell by your symptoms which virus is making you unwell. You can usually only tell which virus it is by sophisticated molecular pathology testing on a sample from your respiratory tract.

It’s commonly stated rhinovirus and common cold symptoms are different to influenza (the flu). However all the viruses mentioned can cause an influenza-like illness. Most people infected with influenza virus have only mild symptoms or are asymptomatic. Many infected with influenza have exactly the same symptoms as those infected with rhinovirus.

This is why it’s usually not possible for you, or a doctor, to tell whether you are suffering from a cold or flu. The term “ILI” or “influenza-like illness” is also used for colds, especially where there is also fever.

While influenza might sometimes be associated with more severe respiratory infections, rhinovirus gives it a good run for its money. During most winters, rhinoviruses cause more cases of people needing admission to hospital with pneumonia than do influenza viruses.

What can we do about them?

The common cold is caused by viruses so antibiotics do not work and should be avoided. They won’t kill the causative viruses but just give the individual side effects and needlessly help cause antibiotic resistance to rise as well.

There are few good studies that have looked at what works for the common cold. Many things don’t work. As well as antibiotics, vitamin C, vitamin D and echinacea also don’t work.

Antihistamines don’t work by themselves but may be of benefit if combined with a decongestant and analgesic. Decongestants are only of small benefit if used by themselves. An anti-asthma drug (ipratropium) if used intranasally probably benefits in the relief of some symptoms.

Over-the-counter cough treatments and vapour rub don’t seem to be of benefit. Anti-inflammatories such as aspirin and ibuprofen help relieve pain and aches but don’t seem to benefit control of other symptoms.

Paracetamol helps fever as well as pain, but it doesn’t work as well as ibuprofen for fever control. Humidified air, nasal irrigation and ginseng are all of unclear benefit. Oral zinc as lozenges does appear to be of some benefit. Honey might help but so does chicken soup – especially if made by your mother!

As we head towards a southern hemisphere winter, many people are wondering if it’s worth getting the flu vaccine.

Generally speaking, if you are vaccinated, you’re less likely to get the flu. But that’s not the whole story.

For most healthy people, it’s about considering the cost and a few seconds of pain against the possibility that you’ll need to take time off work and endure a few days of misery due to infection.

For people who come into contact with vulnerable people – like the elderly, young or sick – getting vaccinated reduces the risk that you can pass it on.

For vulnerable people, the flu can be the difference between being at home with a chronic disease, and being in hospital with complications such as bacterial pneumonia.

When you should get vaccinated is a bit like playing the lottery. If you are vaccinated too early, there’s the risk it doesn’t work when you most need it; too late and you may get the flu while unprotected, or forget to have it before flu season hits.

Here’s what you need to know when deciding whether to get vaccinated, and when.

Preventing influenza

People who get vaccinated are at lower risk of getting influenza than those who are not. They are less likely to be laid up in bed with sweats, shivers and muscle aches, and take time off work or their usual activities, or be hospitalised with complications.

The Australian government recommends everyone from six months old be vaccinated, with those in the following higher-risk categories eligible for a free shot in 2017:

• people aged 65 years and over
• Aboriginal and Torres Strait people aged six months to less than five years
• Aboriginal and Torres Strait Islander people who are aged 15 years and over
• pregnant women
• people aged six months and over with medical conditions, like severe asthma, lung or heart disease, low immunity or diabetes that can lead to complications from influenza.

The mild symptoms that some people get after vaccination are usually related to the vaccine generating an immune response. This is how vaccines work – by “training” the immune system to recognise parts of the influenza virus, it can respond more effectively when it encounters the real thing. There is no “live virus” in the flu shot. Your body responds to parts of the flu virus in the vaccine; you cannot “catch the flu” from it.

All brands of flu vaccine available in Australia are safe; researchers are continuing to monitor for any side-effects week-by-week using SMS feedback from people who have been recently vaccinated.

Like all medications, the flu vaccine carries with it a small risk of side effects, like temporary soreness at the injection site.

The flu vaccine doesn’t provide complete protection

Most clinical trials that have looked at how effective the flu vaccine is were performed in healthy adults and children. However, the people for whom we strongly recommend flu vaccine are those who are older and with chronic illnesses. Unfortunately the vaccine doesn’t elicit as strong an immune response in these groups. They are targeted for vaccination because of the high risk of complications.

In Australian studies, we generally estimate the risk of influenza is reduced by about 40-50% in people who receive the vaccine.

While this might seem low, reducing the risk of infection by half is worth the effort.

There are a number of different strains of influenza, which are categorised into types, subtypes and strains. For example, one of the four strains in the 2017 vaccine is called A/H3N2/Hong Kong/4801/2014, which refers to an influenza A type, a H3N2 subtype (flu viruses are defined and named by proteins on their surface, haemagglutinin – H, and neuraminidase – N), and a strain first isolated in Hong Kong in 2014.

In a typical year, there are usually three subtypes (in varying proportions) of the influenza circulating that cause disease. Except in pandemic years, the circulating strains are usually variants of the previous season’s strains, and this allows the World Health Organisation to make recommendations on which strains should go into the next season’s vaccine.

Occasionally, the vaccine strains aren’t well matched to circulating strains. This risk of mismatch has been reduced by the quadrivalent vaccine that contains four strains.

Protection from the flu doesn’t last that long

In most of Australia, the peak flu season usually runs from August to September.

But the flu vaccine produces a relatively short-lived immune response, about 6-12 months after vaccination. This is because the flu vaccine produces a weaker immune response than being infected.

How long it provides protection probably depends on the patient (some studies show elderly patients have a shorter immune response) and the virus (some influenza subtypes elicit a stronger immune response than others).

So there is some concern that if people are vaccinated too early in the year, their immune response might be starting to decline just when it is needed.

Studies that have looked at how important this is have shown conflicting results. While one study found the effectiveness of the vaccine against the A/H1N1 and A/H3N2 strains declined after three months, the other study found a decline only against A/H3N2 and B strains.

In the meantime, we generally recommend April to June is probably the optimal time for vaccination – early enough for your immune system to “learn” how to deal with the influenza virus for the peak flu season, but not so late you miss the peak flu season.

For doctors, there are other factors involved in deciding when to vaccinate a patient. If they don’t vaccinate a patient now, will they come back again before the influenza season hits? Are they are risk of getting influenza “out of season”?

Although most flu cases occur in winter, we are increasingly aware of cases that occur throughout the year. This is particularly important in tropical regions where influenza tends to circulate all year round.

These include various stereotypes – for example, the image of a typical breast cancer survivor portrayed sympathetically in books, on television and in public health campaigns – which have effectively narrowed our cultural understanding of cancer.

This means those with the disease are exposed to a range of cultural logics that misrepresent the experience of cancer, and can even induce distress and shame.

People judge

Cancer is a disease that not only brings worry and fear, but also clear messages about what we can do to prevent it. This is especially the case for the “lifestyle cancers”, caused by our own behaviours or lifestyle factors. Around 80% of lung cancer cases, for instance, can be attributed to smoking.

Social assumptions have important implications for people living with cancer. And while “taking ownership” in response to having cancer can be useful for some, it can lead others to question what they may have done wrong to get it.

In our recent study of 81 women with diverse forms of cancer, we found simplistic social understandings of the disease are often damaging for those living with it.

Women across our study articulated feelings of blame and judgement based on the reactions of others. Comments included:

You’re suddenly this person who deserves to die because you smoked.

She [doctor] turned around and she goes, “You did have symptoms and you didn’t come for a pap smear for a long time, what do you expect?”

Some women described being held up as examples of what not to do:

…even my daughter made a comment to the children… she said, “Nan’s got lung cancer, because of the smoking”… You feel guilty. You think you’ve done something really wrong.

Our work shows people have clear ideas about how much cancer patients contribute to their own illness.

This is especially so when it comes to lung cancer, most cases of which are caused by smoking; and in the case of cervical cancer and head and neck cancers, which can be associated with the sexually-transmitted human papillomavirus (HPV). The now recognised role of HPV adds another layer of potential blame to the development of cancer in women.

You ‘deserve’ it

Lung cancer in particular is surrounded by stigma. Australians show less sympathy for people with lung cancer than those with other forms. A recent report found out of 15 nations surveyed, Australians had the least sympathy for people diagnosed with lung cancer.

Such a climate can make people feel further stigmatised and ultimately responsible for their illness, as if they deserved to get it. This can make it challenging for them to then reach out or receive help, regardless of whether they smoked or not.

The judgement and stigma attached to “bad behaviours” and lifestyle diseases also discounts the fact of the social gradient of health – that wealth is a protective factor in developing cancer. People in higher economic positions have better access to care and private health coverage, and better health outcomes.

Australians in lower socioeconomic positions are left at greater risk of developing life-threatening illnesses.

Read more: Social determinants – how class and wealth affect our health

All this has seen a hierarchy of public and financial support for different forms of cancer emerge, in line with perceptions of deservedness. This has resulted in highly unequal support across cancer types.

Despite killing three times as many people as breast cancer, lung cancer receives only a fifth of the research funding. Reflecting on the attention divide, one woman with cervical cancer told us:

I know that there’s obviously not anywhere near as much [support] as there is [for] breast cancer and at the beginning of my treatment I was a bit offended by all of the pink stuff. I was like, “Enough of the breast cancer”.

We’re all human

Public health campaigns encourage us to regularly have cancer screening, eat healthily, exercise, quit or avoid smoking or drinking too much alcohol, and so on.

While it’s important to take care of ourselves, we need to remember that not all cancers are preventable. The fact is, one in two men and one in three women will develop cancer in their lifetime, often regardless of their life choices.

Think of the stories we hear of completely healthy people who develop brain cancer out of the blue, or relatives who smoked all their lives yet died at the age of 95 from old age. These stories remind us that cancer does not always develop in predictable ways.

For various reasons, a lot of public attention, support and generosity is given to people living with prominent, visible or less blameworthy illnesses. Yet others can experience feelings of shame, blame and illegitimacy because of some people’s reactions.

These unequal degrees of compassion need to be adjusted to support people regardless of how well understood or visible their illness is. The idea of certain cancers being a person’s responsibility undermines the need to provide support and care to all those living with the disease.