Home U.S Dr. Nicole Saphier: Reaching immunity from coronavirus – here are things to watch...

Dr. Nicole Saphier: Reaching immunity from coronavirus – here are things to watch as country moves forward


As infections, hospitalizations and deaths decline across the country, people are clamoring to return to a life that resembles a modicum of normalcy, more specifically, pre-COVID normality.   

Following a devastating winter, the country is now witnessing the effects of growing immunity. The first vaccine dose outside of clinical trials was administered Dec. 14, 2020, and now over 65 million doses have been given, according to the NPR vaccine tracker. The growing vaccine-induced immunity is quickly adding to the existing exposure immunity that has been building since Jan. 21, 2020, when the first U.S. case of COVID-19 was reported. 

As we head into March, a third COVID-19 vaccine has received an EUA and more than 40% of Americans over 65 years of age are vaccinated with at least one dose. Now is certainly the time to begin acknowledging our country is becoming less vulnerable to this pathogen. Because of such, we should determine mitigation strategies and risk of infection differently as more of the vulnerable become protected.


As Dr. Marty Makary, professor at the Johns Hopkins School of Medicine and Bloomberg School of Public Health, pointed out in a Wall Street Journal piece recently, when you extrapolate documented COVID-19 infections with seroprevalence studies and other modeling, it is likely “about 55% of Americans have natural immunity.”

In combination with fast-growing vaccinated immunity, the data suggest we’ll hit herd immunity by late spring, a conclusion echoed by former FDA Commissioner Scott Gottlieb last week. 

While epidemiologists and other health care professionals are relishing the favorable decline in disease transmission, the rest of the country is wondering what’s next. 


Despite the likelihood the United States reaches a level of protective “herd” immunity by late spring, Dr. June McKoy, a geriatric specialist from Northwestern said during an interview, “We will still need to socially distance and wear our masks. We should avoid our frail elders, because we just do not know the strength of their immune response to the vaccine and whether they have built up sufficient antibodies.”  

During a White House press briefing last week Dr. Anthony Fauci, chief medical adviser on COVID-19 for President Biden, said, “There are things, even if you’re vaccinated, that you’re not going to be able to do in society. For example, indoor dining, theaters, places where people congregate.” He further went on to say that unless the majority of people are vaccinated and viral transmission is “way down,” he continues to recommend mask wearing. 

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But are these data-driven recommendation or dogma? 

A year into the pandemic we now have two populations, the immune and the non-immune. They carry different risks. It is extremely difficult to implement a single society-wide mask and distancing recommendation as we did in the past, with today’s immune and non-immune populations.  

Questions remain as to how long immunity will last and if once immune if those are still able to infect others. One recent study found that natural immunity is still present in people eight months after they were infected.  Another study noted that the immune response to COVID-19 is comparable to those of who recovered from the original SARS in the early 2000s. Because of this, it is possible to deduce that there may be some level of long-term immunity to SARS-CoV-2 that may last for several years, as studies have shown for SARS.   

While we don’t have data yet to confirm our hypothesis that vaccines result in much less transmission, vaccines are reaching 95% to prevent modest and severe infection. Transmissibility is linked to viral load. Thus deductive reasoning would tell us that the transmission risk of a vaccinated person is very low.  Further adding to the optimism about low transmission following vaccination, early data from Moderna and AstraZeneca suggest a level of protection following vaccination against asymptomatic infection. 

Rising community immunity points toward liberation in the next few months.  

Yet, our experts are still waxing and waning on whether we can do just that. 

Rising community immunity points toward liberation in the next few months.  

We should adapt public health measures to the background level of infection in the community. The percent of tests performed that are positive (percent positivity) is a critical measure illustrating how widespread transmission is in an area.  Most state re-openings were based on percent positivity levels beginning May 2020 after the World Health Organization suggested that if the percent positive remains below 5% for at least two weeks, reopening should occur. Fast forward to now, newly reported Johns Hopkins data shows the seven-day average percent positivity in the United States is 5.9%, with daily numbers dipping below 5%.  Currently over half of the U.S. states are reporting less than 5% positivity and soon many more are to follow.  

Once local percent positivity levels are consistently below 5%, mask mandates and indoor restrictions should be removed.  While we may see a small rise in cases following spring break, by May, the majority of the country should be below 5%.   

Until then, there is nothing stopping someone from choosing to wear a face mask, but when individuals with immunity are gathering together, self-selective masking should suffice as I have yet to see conclusive data demonstrating cloth masks to have anywhere near the effectiveness at preventing COVID-19 as seen with immunity. This should not come in the form of an immunity passport as there are many variables that would render them inaccurate, including some who have been exposed to the virus with natural immunity who do not realize it.  

The novel coronavirus that has been circulating the globe since January 2020 is likely to become endemic, meaning that it will be with us for years to come. As with the flu and other endemic pathogens, we won’t get to an absolute zero risk reduction. 


In the fall, new and existing viral variants threaten of a small wave, so we may need to reevaluate recommendations and modify vaccines based on localities the way Asian cultures have been doing for decades. Following the SARS outbreak in the early 2000s that killed 800 people, many Asian countries began having high risk individuals wear a mask when necessary as well as anyone with symptoms of a respiratory illness and those who have been in close contact with a known infected person.  

The realistic goal is not to achieve an absolute, but rather to focus on mitigation efforts while moving forward. The more people who get vaccinated, the better positioned the country will be. 



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