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Ask Dr. Halverson: Asymptomatic transmission of COVID-19

web 4 17 Halverson photo
A reader asked, “What is the medical basis for wearing a mask after vaccination? And for how long?”
We wear a mask to protect others from catching COVID-19 from us. More than 50% of cases are acquired through asymptomatic transmission. Asymptomatic transmission of the SARS-CoV-2 virus, which causes COVID-19, is one of the most difficult challenges we face in ending the pandemic. Simply put, the virus is so highly contagious that people who have been exposed and have acquired the virus, but have not yet developed symptoms, can spread it to other unprotected individuals. 
In fact, many infected individuals, particularly people with more robust immune systems, may never develop symptoms, yet pass the virus on to others who are much more susceptible.
SARS CoV-2 can spread in three ways:
— Spread of the virus by touching infected surfaces (fomite transmission) is the basis for hand washing and sterilization of surfaces.
— Droplet transmission occurs when an individual is exposed by a sneeze, cough, laughter or other means that directly propels the virus in droplet form. It occurs primarily within 6 feet of an infected individual and is the basis for maintaining that distance from others.
— Aerosol transmission, which occurs when we inhale the virus that has been spread by the simple act of breathing or talking by an infected individual, is the primary cause of asymptomatic transmission.
Think of aerosol transmission as similar to the spread of smoke from a nearby smoker. We may not see the smoke after it is exhaled, but the smell of it can linger in the air. If we are outdoors, the smell goes away fairly quickly. If we are indoors, it may linger much longer. In this same way, the virus may linger in the air for several minutes, especially in places with poor ventilation. If an asymptomatic person with COVID-19 is not wearing a mask, someone else in the room can inhale enough of the smoke (virus) and the virus can become established in their airways and begin to replicate.
Many studies have indicated that more the 50% of infected people will develop few or no symptoms. However, they may carry the virus for up to several days while their immune system gradually eliminates it. During this time, they are able to spread it to others. This is the basis for asymptomatic spread.
Back to the question regarding wearing a mask after being vaccinated. Studies have shown that the vaccine reduces the incidence of symptomatic infection by approximately 95%. However, it is not yet known if it reduces the incidence of asymptomatic infection. With a much more robust immune response due to the vaccine, vaccinated individuals may not develop symptoms, but may still carry the virus for several days while their immune system gets rid of it. More susceptible individuals, especially those who have not yet been vaccinated, could still get infected from them. 
How will we eventually be able to discontinue mask wearing? As more people are vaccinated and we continue to follow all the recommended safety measures (mask wearing, social distancing and hygiene), we will succeed in lessening the number of cases, progress through California’s four tiers of reopening and eventually be able to resume a much more normal lifestyle without masks.

 

CMHS system very well prepared for current surge
The Community Memorial Health System is composed of our Ojai Valley Community Hospital and Community Memorial Hospital in Ventura. I am so appreciative of the preparation and responsiveness of these two hospitals to the pandemic. This has been most evident in the recent surge of COVID-19 in Ventura County over the last several weeks.
Both hospitals have developed their response through excellent planning since the pandemic began. Four critical areas that are constantly being addressed are space, supplies, staffing and communication.
SPACE. As of Jan. 12, there were nearly 90 patients hospitalized with COVID-19 at CMH and that number is likely to rise in the coming weeks. We are fortunate that CMH in Ventura has two buildings currently that are licensed to care for inpatients. The new hospital (Ocean Tower) has been able to devote the entire sixth floor to the care of COVID-19 patients only. Each patient is in a separate room with staff extremely well trained and experienced with dealing with the unique challenges of this disease.
To keep adequate space in the new hospital, our administration has reopened the seventh floor of the prior hospital (Mountain Tower) to care for some of the non-COVID-19 inpatients. In addition, Ojai Valley Community Hospital has not admitted any COVID-19 patients, transferring all from our emergency department to CMH. This enables our local hospital to take non-COVID-19 patients from CMH to continue their care if more beds are needed for COVID-19 patients at CMH.
CMH also has 28 ICU beds and 32 ventilators to care for the most critically ill with COVID-19 or other medical or surgical conditions. More beds can be converted to ICU level of care if needed.
SUPPLIES. We are currently in very good shape with personal protective equipment supplies at both hospitals. We have a great team devoted to ensuring that adequate amounts of proper masks, gloves, face shields and gowns are always available. It is vitally important that the staffs at both hospitals are kept safe and healthy so they may remain available to help care for us if we become ill or injured and require hospital care.
STAFFING. The lifeblood of any hospital is having enough staff to provide excellent care. Both hospitals have excellent protocols to test staff frequently, quarantine immediately if necessary and contact trace rapidly. Although it is impossible to prevent any staff from becoming exposed outside of the hospital, this diligence in testing helps keep the number of available staff numbers as high as possible.
COMMUNICATION. Our combined medical staffs at CMH and Ojai Valley Community Hospital participated in a Facetime Town Hall meeting last week. Nearly 200 of us gathered remotely and were given the latest updates on hospital protocols and procedures and the challenges that we face in guaranteeing excellent care for our hospitalized patients and hospital staff. Communication through emails and online meetings will continue.
We are at a very difficult time with this pandemic in Ventura County.  The number of hospitalized patients with COVID-19 is much higher than ever before. The current surge in cases will continue for awhile due to the recent increased exposure of people through holiday gatherings and travel. Please heed the call to continue your efforts to follow all of the recommended personal measures to protect yourself and others.
Stay committed, stay properly informed, stay positive, stay safe and stay well.
— Dr. Jim Halverson is a longtime Ojai physician who writes a weekly column on COVID-19 for the Ojai Valley News.

 

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