What You Really Need To Know About Covid-19. Advice From Pia MacDonald, MPH, PhD.

The timing could not be any better! We had the chance to hear a presentation by Pia MacDonald, PhD, MPH, CPH, from RTI International last week. Pia has two decades of experience in domestic and international epidemiological research and public health. She has an extensive background in infectious disease epidemiology and surveillance, global health security, public health preparedness, and outbreak investigation and response. Please read her expert assessment of the COVID-19, also known as Coronavirus, situation.

IN A NUTSHELL:

"Looking closely at the data from China, the WHO-China Joint Mission COVID-19 report indicated that most transmission occurs within households, NOT within the health care settings, or in airports, planes, trains or on streets."

"In the US, to be clear, this is no longer a travel associated outbreak. There is community acquired infection, so the outbreak is domestic and global."

PRESENTATION IN 3 PARTS

• COVID-19 in the context of other outbreaks
• Why the outbreak now, and why Dr. MacDonald is not surprised
• “The Good, the Bad, and the Ugly”

Let's jump right in!
Novel Coronavirus disease 2019, now known as COVID-19, is zoonotic.
Zoonotic diseases are those that normally exist in animals and can be transmitted from animals to humans.
Generally, they tend to be more lethal than other infectious diseases.
Examples of zoonotic diseases include: Ebola, Anthrax, Plague, Hantavirus, and some forms of Influenza.
Coronavirus diseases from a historical perspective were considered relatively inconsequential viruses.
They circulate globally and cause between 10-30% of the common colds.
Similarly, various coronaviruses circulate in mammals and birds.

Recently, we have seen three lethal zoonotic coronaviruses effecting humans.
In 2002-2003, there was an outbreak of Severe Acute Respiratory Syndrome, or SARS, which started in China, spread to Hong Kong, Canada, and other countries.  SARS had a case fatality rate of 9.5%.
Case fatality rate is the percentage of sick people who die.

Then in 2012, Middle Eastern Respiratory Syndrome or MERS emerged, in the Middle East.  It has a case fatality rate of 34%.
MERS is still causing sporadic outbreaks, originating from the Middle East.
While SARS has disappeared since the first epidemic.
Now we have COVID-19, a 3rd deadly-to-humans coronavirus.
To see how COVID-19 compares to other diseases, let us take a close look at this graph.

The x axis has the transmission rate. This is the average number of people a sick person infects.
And the fatality rate is on the y axis.
So the higher up, the more deadly, and the further to the right, the faster an outbreak can spread.

Let's look at MERS:
38% of people with MERS die, and before they die, they infect less than one person, therefore its not very effective at growing into a large outbreak.
Keep in mind that MERS is spread mostly through people coughing and sneezing on others.

Measles falls on the far right, 1 sick person infects on average 15 other people, while only 1 out of 100 people will die from it.
This means that outbreaks can grow very fast.
Measles is unusual as far as infectious diseases go.
It's highly infectious because the virus can be airborne, meaning it can be suspended in the air for some time.

The data is showing that COVID 19 falls somewhere between the Spanish flu of 1918 and Polio.
The latest estimate is that 1 person with COVID 19 gives the disease to 2.3 people.
WHO announced this week that the current global estimate is that COVID-19 has a case fatality rate of 3.4%.  However, this estimate, is just that, an estimate based on current understanding of the outbreak.
It is VERY important to recognize that this rate is different depending on age and health status.
We are seeing the elderly, immunocompromised, and people with underlying health conditions have higher fatality rates.  While others have much lower rates.

How does COVID-19 spread and what is driving the outbreak?
So far, the limited data suggest that COVID-19 transmission is similar to seasonal influenza.
Close contact with sick people, who are coughing and sneezing, will put a person at the highest risk of infection.
It is spread mostly by droplets – so having a sick person wear a simple surgical face mask is a good idea.
Unlike measles, early data suggests that the virus does not stay suspended in air for long.

Looking closely at the data from China, the WHO-China Joint Mission COVID-19 report indicated that most transmission occurs within households, NOT within the health care settings, or in airports, planes, trains or on streets.
Again, household transmission is what was driving the outbreak expansion, similar to other colds and the seasonal influenza.  Household transmission, generally, can occur with close and sustained contact with sick people.

For COVID-19, the most common symptoms seem to be fever and a dry cough, with some people experiencing shortness of breath or difficulty breathing.  Generally, less than 20% of sick people experience severe disease.

Why now?  Why as an infectious disease epidemiologist, Dr. MacDonald is not surprised about the recent outbreaks such as Ebola, Zika, and now COVID-19.
There are global changes amidst that are creating conditions that may be driving zoonotic disease emergence and increasing risk.

The world’s population doubled since 1960, and is slated to double again within the next 40 years. There has been major growth recently in Asia, and next the massive growth is expected in Africa.
Over 50 percent of the world population now live in cities.
There are 38 mega-cities, cities with over 10 million people.
By 2050, there will be many more mega-cities, and 2/3 of the world’s population will be living in one.
With such growth of populations in cities, the infrastructure development will likely not keep up, resulting in high density dwelling, crowding, and inadequate sanitation.

The massive population growth will accompany significant economic growth, and with that a growing demand for animal protein.
Already, the growth of pig and chicken farms has been exponential in areas of China and India.
Further globalization of goods, services, and people movement are also drivers.
With air travel, we are seeing annual growth rates within Asia of 6%, Africa 5%, and Middle East 7%.

What alarms Dr. MacDonald, is that we know where the risk of zoonotic disease emergence is greatest.  We create great models generated with the best data available.

In this map, note the areas with YELLOW, these areas are where the risk is highest of zoonotic disease emergence.Wuhan lands right in the YELLOW.  AND, It’s a mega-city with 11 million people, it’s also a transportation hub with 1 million people a month flying from there to other parts of China and the worldBy 2050, there will be many more mega-cities in China, India, Nigeria – areas already in YELLOW.
Back to the COVID-19 outbreak in ChinaThe good news is that the China outbreak seems to be waning, meaning that there are fewer cases each day.Of note, China’s response has been the most ambitious, agile, and aggressive disease containment effort in history.It restricted movement of people into and out of Wuhan and 12 other neighboring cities. People were instructed to stay at home for a month, they implemented social distancing measure like closing schools, public transportation, and suspended public gatherings. They had thousands of people tracking sick people and their close contacts to make certain they were isolated from other people. The Good NewsWe have all learned from China.We have insights of how best to treat the sick so they are less likely to die.We have a better understanding of who is at highest risk of severe disease.There are identified public health measures that work: Case detection, rapid diagnosis, isolation, early treatment, contact tracing, and limiting household transmission.

In the US, to be clear, this is no longer a travel associated outbreak. There is community acquired infection, so the outbreak is domestic and global.

We are gaining more capacity to test for the disease by the day.  This week we finally have testing available in the state laboratories and not just in the CDC in Atlanta.Vaccine development is moving quickly. It could be available within a year, with additional time to scale. The BadSome bad news…Until a vaccine is available, we need to do everything to stall the spread and minimize risk. So far, in China they found that 1 person gives the infection to 2.3 people, so the outbreak can grow quickly, 1 to 2, to 4, to 8, to 16….With a 3.4% case fatality rate, the more people who get infected, the more deaths will occur.While it seems relatively contained within China, its spreading globally quickly.Meanwhile, we are seeing big disruptions with the global supply chain.Eighty percent of active pharmaceutical ingredients manufacturers are located outside of the U.S, the majority in China and India.This could impact on our ability to adequately treat patients.

The UglyThe public health measures that we know work will be difficult to achieve in most areas of the world, especially where health care and public health systems are weak.
Lower and middle income countries will be hit far worse than high income countries.
Beyond the COVID-19 outbreak, we are seeing a steady rise in outbreaks and global epidemics then ever before.
What keeps Dr. MacDonald up at night is that only 1/3 of the countries in the world currently have the capacity to quickly detect and report diseases that could pose an international threat.
We are not prepared, now or for the future.  This is true at home here in the US and globally.
Prevention, detection, and response to disease outbreaks requires an all of society approach and support from all sectors.
We need to advocate fiercely for increasing and sustaining public health preparedness and global health security funding.
The time is now to decrease our present and future risk.
Similar to the adage, parents are only as happy as their least happy child, from a global health security perspective, “We are only as safe as our least safe country.”

To stay safe, minimize your risk in the same way you would for seasonal influenza.Wash your hands with soap and water frequently.Stay home if you are sick or if someone in your home is sick.Make plans with your family in case you do need to self-isolate at home.Make plans in your work place.Consult the US Centers for Disease Control and Prevention and state and local health departments for guidance.
Dr. MacDonald did not wear a mask en route to give the presentation.  She will continue flying, though she will move if sitting next to someone coughing or sneezing. And, she will want to give them a face mask.

So do we - we continue traveling and working while taking precautions as recommended. 

Pia MacDonald, MPH, PhD, is an infectious disease epidemiologist at RTI International and Adjunct Associate Professor at the University of North Carolina Gillings School of Global Public Health, Department of Epidemiology.

Dr. MacDonald has 25 years of experience in epidemiologic research and public health, both nationally and internationally. Her work has focused broadly on infectious disease epidemiology and surveillance, outbreak investigation, public health preparedness systems, and global health security. She has worked on outbreaks related to Ebola in West Africa, Zika, H1N1 Influenza, HIV, foodborne diseases, Hepatitis, anthrax, malaria, and many more. She has written more than 65 peer-reviewed publications and a book titled Methods in Field Epidemiology, which is used to train students and practitioners alike.

During her career, she has worked with the U.S. Centers for Disease Control and Prevention, National Institutes of Health, Pan American Health Organization, Council of State and Territorial Epidemiologists, the National Association of County and City Health Officials, North Carolina Division of Public Health, and many others.  Her state- and federal-level public health experience started with her service as a U.S. Centers for Disease Control and Prevention Epidemic Intelligence Service Officer. Her international work began as a Peace Corps volunteer in Thailand, and has since included other countries such as Guinea, Democratic Republic of the Congo, Kenya, Guatemala, Nicaragua, and Turkey.