Why is social distancing so important?

There has been much discussion around how the novel coronavirus, SARS-CoV-2, which causes COVID-19, is transmitted from person to person. How does it spread? How can we monitor, isolate and control the spread of COVID-19? Why is social distancing so important?

A recently published paper, provides new evidence which adds to our understanding of transition dynamics.

The study looked at viral loads in upper respiratory tracts of 18 people from Zhuhai in Guangdong, China. 14 of these people had recently returned to Zhuhai from Wuhan and 4 were ‘secondary infections’ i.e. they had not been to Wuhan. Swabs were taken at regular intervals as the infection progressed.

  • 13 had signs of pneumonia on CT scans
  • 3 required admission to intensive care
  • 15 had mild to moderate illness
  • 1 had no symptoms
  • None had visited the Huanan Seafood Wholesale Market

The paper describes the relationships between the people in the study. For example, one patient worked in Wuhan. He visited his wife, mother and a friend on January 17th. His wife and mother developed symptoms 3 and 5 days later and had virus detected soon after symptoms started. The friend had no symptoms but he too had positive swabs on days 7, 10 and 11 after contact.

The team also looked at viral load in the nose and throat of the patients who had symptoms from the day that their symptoms started. High viral loads were detected very soon after symptom onset, with more in the nose than the throat. There was similarity in the viral load of the symptomatic and asymptomatic patients. This suggests that asymptomatic carries can spread the virus too.

This is different to SARS, which caused a global epidemic in 2002-2003 with over 8000 cases in 25 countries, and suggests that very different case detection and isolation strategies are required to manage and control SARS-CoV-2.

For COVID-19, even people who have mild to moderate symptoms can be highly infectious, and they are very infectious very quickly, perhaps even before symptoms develop or very soon afterwards. This is why social distancing is so important.

Please follow official advice for social distancing, self-isolation or shielding depending on your circumstances.

  • Social distancing is something we should all do to reduce social interaction between people in order to reduce the transmission of coronavirus (COVID-19)
  • Self-isolation is what people should do if they, or someone they live with, develop symptoms that may be caused by coronavirus.
  • Shielding is a measure to protect people who are clinically extremely vulnerable by minimising all interaction between those who are extremely vulnerable and others.

Corticosteroid use and COVID-19

Today (30th March 2020), we noticed a sharp increase in the number of visitors to a particular page of the Aspergillus Website.

The page is called ‘Medications that Weaken Your Immune System and Fungal Infections (CDC)’. We know that many people are worried and struggling to understand if and how their susceptibility to infection with SARS-CoV-2 (COVID-19) is changed by their existing medications.

It is worth noting that the article on the Aspergillus Website is written with specific reference to how medicines, such as corticosteroids and TNF (tumor necrosis factor) inhibitors, increase the risk of fungal infections. It is not written about bacterial or viral infections.

Many medications for asthma, which lots of people have in addition to allergic aspergillosis, contain corticosteroids that are inhaled. Currently, there is no evidence that people who use inhaled corticosteroids are at an increased risk of contracting COVID-19.

The Centre for Evidence-Based Medicine in Oxford has published a useful article on this subject that points out that a COVID-19 infection in an asthmatic may trigger an asthma attack, and it is of greater benefit to the patient to prevent or control that attack than it would be to stop inhaled corticosteroids in an attempt to decrease the risk of  COVID-19 infection. There is even a hint that some types of asthma medication can inhibit coronavirus infection, but the evidence is not based on COVID-19.

Many of our more severe aspergillosis patients also take oral corticosteroids to try to control their breathlessness. During flare-ups, the dose can get quite high for a short time. Needless to say, it is critically important that these patients complete the increased dose as prescribed by their doctor. Patients on long term maintenance steroids must not reduce their dose as this will not offer additional protection against COVID-19. Maintaining good control of your condition is very important in reducing risk of complications. For patients on long term steroids shielding is also particularly important.

Overall, people with chronic (long-term) respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, bronchitis or CPA are considered at increased risk of severe illness from coronavirus (COVID-19) regardless of corticosteroid use. These people should closely follow the guidance on social distancing available from Public Heath England.

Covert infections and the spread of coronavirus

Yesterday, the Prime Minister introduced strict limitations on when and how we can move about and live our lives. He said we should leave our homes only if absolutely necessary. Why is this so important?

The Scientific Journal, Nature, has published an interesting and informative article about the proportion of people with mild or no symptoms of COVID-19 who could be spreading the virus and this information highlights why limiting our movements can help to reduce the spread of coronavirus.

The first important question is how many people are contracting this virus but are experiencing few or no symptoms? It is thought that the number may be quite high because there have been many community acquired infections where the patient has no links to known COVID-19 cases and has not travelled to any area with a large outbreak.

Those people with few or no symptoms may be totally unaware they have the virus and continue to behave as normal. The article calls COVID-19 infections of this sort ‘covert infections’.

Understanding the covert infection rate is crucial if we are to slow the spread of the virus and prevent new outbreaks.

One study that the article reports on looked at 565 Japanese citizens who were all evacuated from Wuhan in February. They were regularly monitored and tested. 13 were infected but 4 (31%) had no symptoms.

The Diamond Princess cruise ship, which was quarantined with 3711 people on board, was another opportunity to study covert infections. There were 700 infections on the ship and 18% of those showed no symptoms. The authors of this study pointed out though that the average age of the people on the cruise ship was relatively high and this could have affected the data because older people tend to experience worse symptoms than younger people.

Finally, there is a suggestion that children may experience mild or no symptoms in 56% of cases.

All of this data show just how important it is to enforce extreme social distancing measures if we are to stop the virus from spreading.

Take a look at the article, it’s available for free on the Nature website.

Asthma and Covid 19 – research findings

An article published in the European Journal of Allergy and Clinical Immunology has described the symptoms and the allergy status of patients with Covid-19.

The study looked at 140 people in Wuhan who were hospitalised because of Covid-19. They were categorised as non-severe (82) or severe (58) on admission, around 70% of the patients were over 50 years old but the age range was 25-87 years old.

The most commonly experienced symptoms were fever (92%), followed by cough (75%), fatigue (75%), and chest tightness or shortness of breath (37%).

64% of the patients had a co-morbidity. The most common of which were chronic diseases such as hypertension (30%) and diabetes (12%). Only two patients had COPD and two had chronic urticaria (an allergic condition of the skin).

No other allergic conditions were reported, including asthma and allergic rhinitis.

This suggests that asthma, allergic disease and COPD are not likely to be prominent risk factors for COVID‐19.

A more recent report, published on 7th March 2020 in the Journal of Global Antimicrobial Resistance, reviewed the currently available literature published in English of microbiologically confirmed infections. It reviewed 225 available studies and seems to support the suggestion that chronic pulmonary diseases such as COPD, asthma and bronchiectasis are less common co-morbidities in people with Covid-19. Cardiovascular, digestive and endocrine system diseases were more commonly reported.

These are just two studies. We still don’t know exactly what the risk factors are. As the scientific community learns more about Covid-19 a more precise picture will emerge. More studies are needed.

In the meantime, government advice is for everyone aged 70 and over, regardless of medical conditions, to follow social distancing measures. Full guidance on the social distancing measures we should all be taking to reduce social interaction between people in order to reduce the transmission of coronavirus is available on gov.uk. This includes information for people with pre-existing health conditions including asthma and COPD. Please read it and follow it.

The full paper in the European Journal of allergy and Clinical Immunology can be read on the Aspergillus Website.

The full report from March 2020, published in the Journal of Global Antimicrobial Resistance can also be read on the Aspergillus Website.

Aspergillus fumigatus and azole resistance in the hospital: Surveillance from flower beds to corridors.

A research team in France have undertaken a screen on indoor air, soil and dust in and around hospitals to look for azole resistant Aspergillus in the environment of the University Hospital of Besançon.

The authors noted that the numbers of azole resistant Aspergillus fumigatus strains that were being isolated from patients, especially cystic fibrosis patients, was increasing. The study was designed to test the air in the hospital to discover if azole resistant A. fumigatus was brought to the hospital from rural environments by prevailing winds. They also wanted to see if plants, trees and flowerbeds around the hospital played a role.

The researchers found 83 azole resistant A. fumigatus isolates.

  • 1 from the air of the intensive care unit
  • 16 from the main corridors
  • 59 from pots of tulips imported from the Netherlands
  • 5 from the soil of trees grown in pots.

No samples of azole resistant A. fumigatus were found from an external sensor, suggesting that the resistant strains collected were not carried into the hospital on prevailing winds.

The tulips may be the main source but the authors are careful to note that to confirm this, genetic analysis would be needed to link isolates found in flower beds to isolates found in the hospital or strains isolated from patients.

In the University Hospital of Besançon, the decision has been made to stop planting bulbs. The results demonstrate a need for increasing vigilance on the surveillance of resistant strains.

The full paper is available on the Aspergillus Website.

A bed of tulips
Soil samples were tested from an outdoor relaxation area planted with tulips and from flower beds in other parts of the hospital.
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