Coronavirus and asthma: what we know so far
When the new coronavirus arrived in early 2020, people with asthma were identified as being at higher risk from the disease. Judgements about who was at increased risk had to be made on the best available evidence—which wasn't much. Data from China was only just emerging and COVID-19 had yet to reach pandemic status.
Given that asthma is a lung disease and COVID-19 targets the lungs, it made sense that people with asthma would be considered at higher risk, as they are from other respiratory illnesses. But as more data emerged, the picture became less clear.
Hospital data represents the tip of the iceberg when it comes to COVID-19 infections. Most people who are infected won't be ill enough to be sent to hospital. Some won't even know they have the disease. But without sustained and widespread testing, it's the only data available.
Early studies from China and the US showed that the proportion of people with asthma coming to hospital with COVID-19 was lower than the proportion of people with asthma in the general population. Yet data from the UK suggests people with asthma are neither over nor underrepresented in hospitalised patients with COVID-19.
It is still possible that people with asthma are more likely to be admitted to hospital with COVID-19 than people without asthma, but issues with the studies are providing an inaccurate picture. It is also possible that the early findings might be genuine, and due to differences in immune responses or protective effects of certain asthma medications.
It is clear that risks from COVID-19 depend on a lot more than whether or not you have asthma, but most of the available data doesn't go into this very much. People with more severe forms of asthma are considered at higher risk. There is hardly any information on how asthma might affect COVID-19 infection in young people because so few children become seriously ill with COVID-19.
Risks appear higher in people recently prescribed oral corticosteroids, which is one type of medication used for asthma. This does not necessarily mean oral corticosteroids themselves increase COVID-19 risk. People with more severe asthma are more likely to be prescribed these medications than people with less severe asthma and, as noted above, people with more severe asthma are considered at higher risk from COVID-19. In fact, some have speculated that oral corticosteroids might help protect against COVID-19, but the evidence for this is unclear.
What the guidance says
As well as the direct risks that COVID-19 infection poses to people with asthma, disruptions and changes brought on by the pandemic may affect asthma outcomes. Diagnosing and routinely monitoring asthma relies on a range of tests administered in face-to-face visits. But, to cut the risks of virus transmission, a lot of these services have been reduced.
Asthma UK has guidance on what people might expect from their usual asthma care at the moment. The advice is that people manage their asthma as well as possible to reduce risk from COVID-19. This includes restarting or continuing prescribed medications and avoiding known triggers, such as air pollution and cigarette smoke.
Some countries now recommend that people wear a face covering (not a surgical mask) in certain settings. Wearing a face covering may be difficult for some people with asthma, and the UK government has advised that people with respiratory conditions don't need to wear face coverings if it is difficult for them to do so.
Finally, it's worth noting that this pandemic has the potential to affect mental health and wellbeing and that this may be even more of a risk for people with long-term conditions, such as asthma. Anxiety and depression are associated with worse asthma control.
The charity, Asthma UK, recommends people with asthma stay active, look after their health, stay social, and ask for support.
While research continues to establish who is at high risk from COVID-19 infection, it's important not to lose sight of the broader ways in which this pandemic may affect people with asthma—and the fact that some groups of people will be more affected than others. Both asthma and COVID-19 disproportionately affect people from more deprived communities and people from non-white ethnic groups. New ways of managing asthma will need to be found and they must be designed to minimise the impact of this double burden wherever possible.