It’s been a very hectic and wonderful couple of weeks, with our MaineHealth teams vaccinating in dozens of middle and high schools. In only the first week since most in this age group have been eligible, 35% of those 12 – 18 years old in Maine have had at least one shot of a COVID-19 vaccine.

However, the most common questions I’ve gotten aren’t on the vaccine, but on masking. And yes, even I was a bit confused after the US CDC’s May 13 announcement of recommendations for those who are fully vaccinated. Here is my take on things.

First, we need to recognize that we’re in a transition. Even if you’re fully vaccinated, I’d carry a mask around. There are plenty of times when you may need it or want it.

Second, the US CDC recommendations from May 13 are for those who are fully vaccinated, i.e., they are at least 14 days from their final dose of a COVID-19 vaccine (second dose of Moderna or Pfizer vaccine or 1st dose of J&J vaccine). The recommendations basically say that fully vaccinated people can unmask and not do physical distancing in most circumstances.

Third, there are major exceptions to these recommendations. The following are settings where the US CDC says people need to still mask:

health care: Fully vaccinated people who are in a health care setting (hospital, dentist office, provider office, nursing home, etc.) must remain masked. I mention this first since we’ve had many people enter our hospitals and practices, thinking they no longer have to mask. The Federal government is clear that masking and distancing are required by them (whenever possible) in health care facilities.


Public Transportation: Those in planes, buses, trains, and other forms of public transportation traveling into, within, or out of the U.S. as well as in transportation hubs such as airports and stations must mask.

PK-12 Schools and any daycare setting for children (since most cannot be fully vaccinated yet), though those under 2 years of age do not need to mask (under 5 years in Maine and some other states).

Correctional facilities and homeless shelters.

Additionally, any local, state, or tribal law or regulation as well as business or workplace policy may require masking in additional settings. Maine’s executive order is aligning with the US CDC recommendations as of Monday, May 24.

There are also some important health exceptions for some individuals who are fully vaccinated. For instance, US CDC recommends that those who are fully vaccinated but immune compromised consider continuing to mask after discussing their circumstance with their doctor. These situations generally include taking immunosuppressive medications after an organ transplant or to treat rheumatologic conditions.

Those younger than 2 years old in any setting (including day care) do not need to mask (age 5 in Maine and some other states).


What will I do? As the news about the efficacy and safety of the vaccines continue to mount, I am feeling more confident about not masking.

The main questions about a particular circumstance in my mind are:

• Will I be in a situation that I will be sharing breathed air with a person or people?

• Do I feel it is safe to share breathed air with that person or people?

There are three areas of emerging knowledge to also consider — vaccine efficacy data, the impact on other respiratory viruses, and ventilation.

Vaccine Efficacy Data to Date

The vaccines offered in the U.S. (Pfizer, Moderna, J&J) are extraordinary in terms of their efficacy and safety. Here is a thumbnail sketch of what we know as well as more nascent knowledge.


Preventing Disease

The data are compelling that the vaccines are highly effective at preventing disease (i.e., when the virus is causing symptoms), including from studies among health care workers in Israel and the U.S. With that said, there will always be some breakthrough cases with any vaccine. Of the 123 million people fully vaccinated in the U.S. as of May 17th, there have been 1,368 people hospitalized and 290 people die due to breakthrough cases. It is felt that many of these are among the frail elderly whose immune systems may not have responded to the vaccine. Some may be due to variants.

Preventing Infection

The data are mounting that the vaccines help prevent infection (and not just disease). An infection without disease would be if the virus can be detected in your nose or mouth, but you don’t have or develop any symptom. However, as is expected, the vaccines do not prevent asymptomatic infection as well as disease. For instance, several studies with the Pfizer vaccine indicate about 80 – 90% efficacy against asymptomatic infection (versus ~95% against disease), though with a wide confidence interval (68 – 97%).

Protection Against Variants

o Studies indicate current vaccines provide good coverage of the B.1.1.7 (U.K.) strain, the dominant strain in the U.S. since April.

o The Pfizer vaccine appears to provide fairly good though less potent coverage (75% effective) against the B.1.351 variant (South African).

o Very little is yet known about vaccine coverage of the B.617 strain (dominant in India) and P.1 (dominant in Brazil).


Secondary Transmission

There are very limited data indicating there may be lower rates of secondary transmission from a fully vaccinated infected person to someone else.

What about other respiratory viruses?

With this focus on COVID-19, there is one major elephant in the room. Influenza. The world has basically skipped over an influenza season this last year. This is astonishing. One likely contributing factor is the precautions put into place for COVID-19 – masking, distancing, hand washing. I have also completely enjoyed the fact that I’ve not had a cold since 2019. As someone with asthma who is also >50, I dread getting colds, since they tend to take a longer and bigger toll on me. I know influenza would be much worse.

The Other V: Ventilation

I think one major enlightenment of the pandemic has been the recognition of how respiratory illnesses are airborne transmitted (not just via droplets that don’t travel that far) and what works to prevent them. Our ancestors went through a similar paradigm shift 120 – 150 years ago when some common debilitating and deathly illnesses such as cholera, typhoid, and dysentery were discovered to be transmitted by contaminated water. Over a period of several decades, the U.S. built an entire infrastructure ensuring people had access to safe water. Today, we will also need a shift in infrastructure to assure the indoor air we breathe is sufficiently ventilated (e.g., exchanged with outdoor air and/or filtrated).

Clearly the vaccine is like wearing a suit of armor. However, like any suit, it is not perfect. As a fully vaccinated person, overall, I feel safe to unmask. In the presence of a person or people whom I may share breathed air with, there are several factors I want to consider:

• Are the other(s) likely to be fully vaccinated?

• Will it be crowded?


• What is the level of pandemic activity or other respiratory illnesses in the state or community I’ll be in? For example, is it flu season?

• Will the setting be well ventilated (e.g., outdoors)?

• How long will I be there?

Assuming I’m not in one of the exceptions for needing to mask (e.g., in a health care setting):

• I currently feel very comfortable not masking with small groups of people (<20) whom I know are vaccinated, whether we’re indoors or outdoors.

• If I’m outdoors or indoors with a large number of people and it may be crowded, i.e., I’m likely to be sharing breathed air with people I don’t know, then I want to assess the situation with the other factors listed above. If it’s not flu and cold season, if COVID incidence is low (<1% test positivity rate, 7-day incidence of ~<5/100,000), if the setting is well ventilated, and if I’m not there for more than an hour or two, then I’m likely going to feel fine to not mask.


For now, if I’m at a hair salon or in a crowded store, I’ll be wearing a mask. I do feel very protected by being vaccinated. However, because of my own risk profile, I know that vaccine plus masking equals even a stronger set of armor.

I’ve masked every day for 14 months, and need to continue to do so while at work, so it is easy for me to do so in other venues. I also understand those who want to throw off the mask as soon as possible.

And then there is guidance for those who are unvaccinated. If I were unvaccinated, besides getting vaccinated as soon as possible, I’d be wearing a mask as US CDC recommends. Children under 12 and older than two need to as well. I feel bad for families of toddlers, since they are unable to wear a mask, leaving the families with dilemmas about taking them to crowded venues where many others may be unmasked.

With all of the focus on masking, the greatest news of the week is that incidence and hospitalizations due to COVID-19 in all 50 states are declining. In some states they are declining to levels not seen since the beginning of the pandemic. Assuming variants that evade vaccine immunity do not emerge, we will likely see sporadic outbreaks. But we are no longer at risk for our health care system being over-run. Hopefully the tragic humanitarian crises in India and elsewhere will subside, and vaccine will disseminate across the globe, providing these extraordinary public health successes everywhere.

Our vaccine teams have been sharing some wonderful stories about vaccinating in our middle and high schools. I had the pleasure of joining one of them last week at Gorham Middle School. As a pediatrician, I’ve administered many vaccines to adolescents. However, I never remember so many of them thanking me for giving them a shot. The excitement among the students was palpable and audible as they received the first half of their ticket to putting this pandemic behind them and enjoying a fun summer.

Indeed, masked or unmasked, it is truly wonderful for so many of us in the U.S. to be stepping into the summer of 2021.

Dr. Dora Anne Mills is the chief health improvement officer for MaineHealth and former head of the Maine Center for Disease Control and Prevention.

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