A not-so-brief update from Dr. Dora Anne Mills
The foliage here in Maine is peaking. It’s even more brilliant this year than most. They say that’s because of the drought we’re experiencing. Apparently dry conditions mean the reds and yellows are more dramatic. As we head into what could be a long winter, it seems like a refreshing blessing for us.
The change of season reminds us of what’s ahead, and it is also a gentle reminder to look back and ask ourselves, what did we learn these last few months that we can carry forward? Indeed, as I think back to last winter, there are several facts about COVID-19 we did not know, and that became surprises. Here are five of them.
First, this pandemic spread like wildfire around the globe with lightning speed. Within weeks of it first being detected in Wuhan, China, you could find it just about everywhere you looked for it. With that said, there are places where the pandemic has exerted a much less severe impact than others. Much of Sub-Saharan Africa, for instance, has been affected by COVID-19, but not nearly to the extent of most of the rest of the world. Is it because the population is younger? Is it because the population doesn’t have the chronic diseases that plague much of the U.S., such as obesity and nicotine addiction (smoking)? Is it related to the tropical location, which for perhaps similar unknown reasons seems to be why influenza does not exert a severe impact on Sub-Saharan Africa? Is it because the infectious disease tracking systems aren’t picking it up as well? Perhaps the reasons why will hold some lessons for all of us.
Second, and related to the first point, the virus appears to be transmitted not only through the usual respiratory droplets, but also through lighter aerosols, which tend to drift farther through the air. The assumption last winter was that this virus is like many other respiratory viruses and transmitted primarily through droplets, which, because they’re heavier, generally do not travel far (e.g. beyond six feet) and fall toward the ground quite quickly. Although there have been a number of headline-grabbing studies showing viral particles many feet away from a coughing patient or found weeks on a surface after being planted there, most of these findings do not mean the virus is viable, i.e. contagious. They often mean only viral genetic particles can be found. However, some recent studies have found SARS-CoV-2 viable virus in the air about 14 feet away from patients, who were unmasked and coughing. In this case, “viable” means the scientists were able to culture it. Additionally, epidemiological studies, e.g. studies of outbreaks, have also indicated that people likely contracted the infection from more than six away from the infected person.
Third, no one predicted last winter that people without symptoms could be major transmitters of this virus. While there is still a great deal of variability in the statistics, it appears that a substantial proportion of people infected with the SARS-CoV-2 virus do not display symptoms (18 – 81%). While most may go on to develop symptoms (and are therefore pre-symptomatic), some of them never develop symptoms. However, all of them can transmit the virus to others and commonly do. It seems that youth and young adults are more likely to be silent transmitters. An estimated 40% of transmission may be from those without symptoms, and this figure could be much higher.
This silent transmission is quite different from influenza. While people can be contagious with influenza one to two days before symptoms, they generally are not effective transmitters. In other words, they may be contagious, but until they have symptoms, such as feeling feverish and coughing, they don’t harbor large amounts of the virus and are not easily spreading it.
This surprise about the silent transmission of COVID-19 has had enormous ripple effects. For instance, it Is why screening for symptoms is important, but also has many cracks. It is why universal masking and other universal precautions are so critical. It is why tracking, quarantining, and testing of contacts – even those without symptoms – is critical. It is also one reason why the pandemic has spread so quickly.
Fourth, the potential for superspreading events was also a surprise. When we started hearing about dozens of attendees from funerals in Georgia, weddings in Chicago, the Biogen meeting in Massachusetts, a birthday party in Wilton, Connecticut, a choir rehearsal in Skagit County, Washington State, it was unclear how common these events were. While there is still uncertainty, it’s clear that while many gatherings go on without a problem, it only takes one to cause an avalanche. Studies show that about 90% of the over 60 attendees at the Skagit choir rehearsal contracted the infection, despite not shaking hands and not hugging, and tragically, three died. Genetic analysis indicates that eventually, around 20,000 in Massachusetts contracted COVID-19 as a result of the late February Biogen conference, in which about 100 of the 175 attendees became sick. When one realizes that many of the 100 were from other states and countries, we realize the 20,000 is likely a far underestimate.
Tragically, we in Maine learned about the potential for superspreading with a wedding in northern Maine causing about 180 or more cases and eight deaths, including igniting numerous subsequent pandemic sparks in York County and elsewhere, resulting in even more cases.
Fifth, we’ve learned that unlike influenza, which is primarily a respiratory infection, COVID-19 is a systemic disease. While most people infected with COVID-19 have respiratory symptoms, such as cough and congestion, they also often have other symptoms, and we know some present entirely with non-respiratory symptoms. For instance, people often report losing their sense of taste or smell. Studies show that a significant proportion of people have cardiac findings, such as myocarditis, an inflammation of the heart muscle. Even young athletes with very mild symptoms can have significant myocarditis. The virus can cause blood clotting, which, when this occurs in the arteries feeding the heart or brain, can cause heart attacks and strokes. We have also seen the virus cause new-onset mental illness, which, fortunately, seems to subside as the virus clears. Are these simply rare reports found in obscure medical literature? No, not at all. In fact, we have seen all of these conditions among patients here in Maine. While it is not completely clear how this virus causes such a variety of conditions, it likely has to do with the fact that the spike protein (the protein that is pictured as thorns sticking out from the coronavirus) binds to the ACE2 receptor on our cells. ACE2 receptors are found in many cells in our body, which may explain how the virus is able to gain entry and exert its toll in a variety of ways. Clearly, COVID-19 is not “just the flu”.
Multiple layers of protection
When we weave all of these surprises from the last few months, one thing is abundantly clear, that we did not fully appreciate last winter: we need multiple layers of protection. Think of these layers the same way as when you go for a walk on a crisp autumn evening. We may put on a long-sleeved shirt, but we also need a sweater, a coat, and a hat. For COVID, the layers of protection include masking, distancing, hygiene, reduced density of people, ventilation, screening for symptoms and/or testing, isolation (for those who test positive), contact tracing, and quarantining (for contacts). And for this fall, we also need flu vaccine.
The first three layers are the most basic, what are called the three W’s — Wearing masks, Watching our distance, and Washing our hands. These should be adhered to at all times when we’re around others, as is possible, especially around those not in our household.
As it turns cold, the big threat is the lack of ventilation as we increasingly gather indoors. What that means is the other layers of protection become more important to adhere to. In other words, when we’re planning indoor gatherings, we’ll need to keep the numbers of people coming together to a minimum, keep them at a distance, and make sure people are masked. When people gather indoors for a meal, this becomes even more complicated since masking – a critical layer – is impossible. Unfortunately, the virus doesn’t care that we’re eating. In fact, eating gives it an opening to infect others. So, keeping the numbers of people low and spreading them out are even more critical layers. Practically speaking, this may mean not eating around a dining room table, but spreading people out so they’re eating around a living room. A household (quarantine group) can eat sitting together on a couch, with others spread farther apart. I recently unexpectedly found my mother’s old tv tray tables in the far corner of a shed behind some old skis and sleds. It donned on me they now have a renewed use. What a pleasant surprise!
The good news is we should have some vaccine available in a few months. With estimates of vaccine being 50 – 60% effective, it may not be a panacea. But it will add a strong layer of protection. Will we need the other layers? Yes, likely, for a while. But as we learn more about the virus and as more are vaccinated, we may also be able to refine the layers of protection. When I think about how much we’ve learned in the last six months, it’s impossible to know what surprises lay ahead. But clearly, they will help us eventually shake free of this pandemic.
Autumn always seems unsettling and bittersweet. I yearn for the carefree endless days of summer. I also enjoy the crisp air and the colors the foliage brings. But I also know this is not the time to pause too long. There is so much to prepare for. Indeed, this year especially calls for us to reflect as well as to prepare.
Dora Anne Mills, MD, MPH, FAAP, Chief Health Improvement Officer, MaineHealth