An expert view on Covid 19, the new Coronavirus…

The majority of experts internationally believe that Covid 19 will continue to be transmitted and countries will see outbreaks. What isn’t known is when and how it will evolve in different regions, and how other factors such as climate may influence the outbreak. Information is coming out from China at a rapid rate and we are fortunate to benefit from studies and research undertaken by the Chinese health authorities. They are to be commended for their rapid response and sharing of data. A recent statement in the Lancet medical journal from international public health experts applauded their response. Currently there are randomised control trials investigating treatments in China and some of these results will be available within weeks which is unprecedented for a new infection and reflects pre-planning by the World Health Organisation and experts in China, and experience gathered from previous outbreaks.

Covid-19 is different from some recent infectious diseases outbreaks and it is for these reasons that it is not possible to control it in the way that SARS and Ebola were brought under control. SARS, also a coronavirus had a much higher case fatality rate but it was not very transmissible. In the SARS outbreak in 2003, many of the transmissions were from sick people in hospitals who had higher levels of virus. The severity of the illness allowed early identification and isolation of cases and prevented onward transmission. Once this was recognised, high-level infection control practices in hospitals, and good contact tracing in the community brought the number of cases under control and eventually it was eliminated. A similar effort brought the EBOLA outbreak under control in West Africa, and during that epidemic effective vaccines were developed and they are now being used in Democratic Republic of Congo.

Thankfully, Covid-19 has a much lower case fatality rate, but conversely this means there are many people who have minor symptoms and they are hard to identify. Covid 19 is much more infectious early in the illness, and the mild illness in the majority of people has made it harder to detect and control. Children have not been seriously affected in figures so far, so the assumption is they have mild disease but they will also transmit the virus in the way other common respiratory infections are transmitted by children. There is always a caution and uncertainty in the fatality rates at the start of an outbreak. People may become ill, receive intensive care treatment and may not succumb to their illness for some weeks, so the initial rate seems lower. If there are a large number of people with mild infection, they will not be counted in an outbreak situation and so the case fatality rate can appear higher than it actually is. This was seen initially with H1N1 (Swine flu) where the initial case fatality rates reported in Mexico were in the order of 6%, but within weeks it was clear that it was much lower and the final rate was 0.1%. It is important to also realise that there are established protocols and factories set up to develop influenza vaccines every year, and the swine Flu vaccine reduced the overall fatality rates.

Fatality rates for Covid 19 are not certain, and presently experts believe it is between 1-2%. However some cohorts have published lower rates. Experts agree the fatality rate is not as high as SARS, but it is higher than influenza. What is also clear is that approximately 14% of people needed hospital care in Wuhan, and that approximately 5% of people needed very high level care. This will strain any health service, and good planning and trying to control transmission in the community will be required to mitigate this. Older adults and those with chronic illness are most at risk. However, the vast majority of people will have mild illness and will not require treatment.

Managing this outbreak requires a coordinated response from public health authorities regionally nationally and internationally. I have no doubt our various public bodies will have been working tirelessly in Northern Ireland over the last several weeks. It is important we adopt a scientific approach to Covid 19 and accept that our epidemiology (pattern of spread in the community) may differ from Britain, and will not follow a political border. The first case in the island of Ireland showed how our island is interconnected but also how our respective organisations were able to co-operate.

From an infectious diseases epidemiological perspective, the island of Ireland should not be treated as two units. It is entirely possible that Britain and the island of Ireland will be at different points in their epidemic curve and will need different decisions to manage localised outbreaks at different times. Since last week, people from N.I. are accessing advice from NHS111 in England. As an extreme example, call handlers could give advice to people from Newry based on what is happening in England, but in actual fact they are unaware that the epidemiology of coronavirus in Dundalk is more relevant. The response and management needs to be flexible to account for the border on the island. Public Health England and Scottish public health authorities have started to test random people with flu symptoms and people with severe pneumonia for Covid 19 even if they haven’t travelled to any of the affected areas. N.I needs to be considered as a different unit from an epidemiological point of view and we will need to know our own epidemiology going forward to allow us to manage cases and outbreaks when they arise.

Dr Claire Donnelly.

Infectious diseases specialist with expertise in infectious diseases epidemiology.

I am not involved in the local response to Covid 19 and all thoughts are my own.

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