Q: Is it helpful to wear a surgical mask?
A: Almost certainly yes. It’s hard to find surgical masks right now, but if you have them, judicious use of the mask with good quality hand hygiene is probably quite effective against the virus. The most useful scenarios are in close contact with other people. The best time to use the mask would not be in wide open spaces where droplet and aerosol transmission is unlikely, but in tight enclosed spaces with other people, especially if these spaces are air conditioned. Here is an article written about the spread of Covid-19 on a Chinese bus. It is speculative and uncontrolled, but potentially instructive in regards to surgical mask utility and spread of virus on public transit.
Q: Can the virus be spread by people without symptoms?
A: Almost certainly yes. There are several medical publications that use known cases and their close contacts to demonstrate asymptomatic spread. Here is one of them. The logic of such papers goes like this: patient 0 comes from out of town and spends 2 days with family members and then leaves town again. On day 3, patient 0 becomes symptomatic and tests positive for covid-19. The family members are tracked down and subsequently develop symptoms despite no other known contacts. The only possibility is that patient 0 became infected prior to visiting and spread the infection during the asymptomatic period.
Q: How does the virus spread?
A: The primary method appears to be close contact with an infected individual. Infected individuals secrete viral particles in nasal mucous (runny nose, sneeze), expectorated sputum (coughing), saliva, and stool. When an infected individual blows their nose, coughs, or sneezes, tiny droplets of mucous fly through the air and can land on nearby surfaces, or your face or hands, or they can be directly inhaled. The virus can infect the nasal mucosa, the cells in the lungs, or it can get into your eye directly or by touching a droplet and then touching your eye. The eye itself does not become infected, but tears wash the droplet into the tear duct which drains into the nose where infection occurs. Direct droplet spread and self-inoculation are likely the primary methods of infection.
The viral RNA can definitely be found on surfaces such as cardboard, plastic, and metal, but to my knowledge, nobody has yet demonstrated that the presence of RNA on these surfaces is definitively infectious. Still, it is best to assume that any surface (including delivered packages) can be contaminated, and to disinfect them to the best of your ability.
The virus may also spread as an airborne aerosol in some circumstances, but this also has not been proven. Airborne/aerosol spread is different than droplet spread in terms of the size of the particle and how long it’s suspended in the air. Droplets usually don’t make it more than 6 feet away from the source before falling to the ground within seconds to minutes. Aerosols could stay airborne for hours and travel much further. Airborne transmission is probably minimal in most conditions — but is probably responsible for some subset of transmissions (this might be especially true in enclosed spaces with turbulent air flow, such as hospital rooms, and public transit.)
Q: What can you do to minimize chances of infection?
A: Wear a surgical mask, wash your hands, stay away from infected people. The WHO and CDC are not blowing smoke on hand washing. Fastidious hand-hygiene is important. I also strongly believe that surgical masks are very protective against spreading this disease. There is a "shortage" of masks, so you might have trouble buying them right now, but if you already have some, they are best used to cover the nose and mouth of infected individuals or to protect oneself in close-contact situations (think public transport, packed stores, etc.) IT IS IMPORTANT NOT TO CONTAMINATE YOURSELF BY TOUCHING THE OUTSIDE OF A CONTAMINATED MASK AND THEN SELF-INOCULATING. The reason for confusing mask recommendations is that some healthcare providers are running out, and a public run on mask supplies would make it even harder for healthcare personnel to get their hands on masks. So, authorities are recommending against masks to maintain supply chains. But, it looks to me like there was a run on masks anyway — people generally don’t trust a recommendation to not protect themselves. So, if you have masks, protect yourself. If you have a lot of extra masks, consider donating them to a major city that is struggling, or a local hospital that is running short. Call your hospital, they should have someone responsible for tracking down and obtaining protective gear.
Q: Are hospitals over-run?
A: Some are. At this point, everyone probably knows that many hospitals in and around NYC are over full-capacity. They are running out of equipment, ventilators, and ICU beds. If you live in or around a major city right now, there is a good chance that healthcare resources are scarce. But, hospitals in more suburban or rural areas have had two plus weeks to prepare and many of them have seen massive cuts to their usual volume. Elective surgeries have been cancelled nationally. Routine outpatient visits have been cancelled. And, anecdotally, it seems like people are avoiding hospitals as much as possible. So, some hospitals have far more capacity than usual, but those in many big cities are swamped, or they’re about to be. Even if your local hospital is well-prepared, this is something that could change quickly. It’s very easy for this virus to take hold in a nursing home or rehab facility and cause people who are already elderly and chronically-ill to all be infected in a short period of time. Several dozen of these patients becoming simultaneously ill would easily consume a major hospital system’s critical care resources. The bottom line is that hospital status is extremely variable right now and depends largely on your local population density and the preparedness of your local health system.
Q: When will this be over?
A: Weeks to months — best case scenario — 8 weeks (Starting on 3/27/20). At this very moment, if we stopped the spread of the virus, we would still have two weeks before we would even know that it was stopped, and likely another two weeks to see how existing cases will resolve. This means we have at least another month of uncertainty, and probably more. Many experts are optimistic that our "social distancing" and warmer weather will slow the spread of the disease, which I think is likely, but I think we’ll see throughout the year bursts of infection as this virus inevitably finds its way into nursing homes, group homes, etc. For the average person, I am optimistic that within 6-8 weeks, we will have a significant national slow-down in spread, robust healthcare responses and preparation, a solid and wide-spread understanding of prevention in terms of mask-wearing and hand-hygiene, and a private sector response in the way of manufacturing tests and supplies.
Q: Are there any useful treatments or preventive strategies?
A: Yes and No. If you’re not yet ill or only mildly ill, there are no treatments other than routine supportive care (antipyretics like acetaminophen, rest, and fluids). If you’re severely (requiring oxygen) or critically-ill (requiring a ventilator), there are several treatments being used. Medications — notably hydroxychloroquine and azithromycin are being used in hospitals to treat severe cases, but the data on these treatments are not promising at the moment. Life-threatening side effects of these medications are real, including sudden-cardiac-death from malignant arrhythmias. See below:
By BruceBlaus — Own work, CC BY-SA 4.0, Link
The top tracing is a normal heart rhythm. It’s called Sinus rhythm.
The waveform below that is called ventricular tachycardia (v-tach). The top rhythm reflects an organized firing of the heart’s electrical system, which causes each chamber of the heart to fire sequentially to maintain normal blood flow. The bottom rhythm shows v-tach, a life-threatening arrhythmia that in some cases can degenerate and cause sudden death if the patient does not receive defibrillation quickly. Below is what the heart looks like when it’s shocked out of v-tach into normal sinus rhythm.
Shock from Vtach to Sinus
It’s because of this potentially deadly complication from medications, along with the propensity of the virus to cause cardiac involvement and increase the risk of arrhythmia, that doctors are hesitant to recommend these medications in the absence of strong evidence that they work.
The mechanism of action of hydroxychloroquine is thought to be the blockade of endosomal acidification. The endosome is a membrane bound organelle within the cell that can harbor viral RNA.
Viral RNA requires certain conditions to travel within the cell and to replicate. One of these conditions is thought to be a particular pH. Hydroxychloroquine may inhibit viral replication by increasing the pH of the endosome, the tiny organelle that houses viral RNA within the cell. Essentially, the supposed mechanism of this medication is to prevent viral replication rather than effect the devastating downstream effects that occur when a patient is critically ill.
So, if the medication is going to work, it probably works best early in disease when the virus has not yet infected lots of cells. But, early on in the disease process, symptoms are usually very mild and the most likely clinical course is recovery (it’s possible that as many as 50% of infected people never develop symptoms at all; of the remaining 50%, only about 1/3 may go on to develop severe or critical illness). With odds this good, taking a dangerous medication is usually imprudent considering the potential side effects, which in some cases can be deadly.
Other treatments under investigation are: Remdesevir (unavailable unless you’re critically ill), and Kaletra (an HIV med that is very expensive, potentially dangerous, of limited availability, and of questionable efficacy). I’ve read that vaccines are already in clinical trials, but expert infectious disease physicians don’t think we’ll have an effective vaccine for 1+ years, and even then, the first to receive it will likely be healthcare workers.
So, essentially, there is no known safe and/or effective treatment that can be taken prophylactically or early in the disease course. Available treatments, though likely of limited efficacy by the time they are used, are best used in severely or critically ill patients. I hope this will change very soon, and it is what I am spending most of my time researching.
Regarding prevention, the best things you can do are to be fastidious about distancing, hygiene, mask wearing, nutrition, sleep, and exercise. Nutrition, sleep, and exercise are incredibly important for immune function. It’s clear that metabolic syndrome (diabetes, hypertension, obesity, fatty liver, and coronary artery disease) puts people at high risk of severe complications. It’s easy to binge on ice cream when you’re anxious and stressed at home, but don’t do it! You’re making yourself less fit and more likely to have a bad complication from infection in the case that it happens. The better thing to do would be to exit isolation in a few weeks in the best shape of your life.
That’s all for now — please feel free to send me questions and I’ll do my best to answer. The best place to contact me and to see what I’m reading is my Twitter account.