Social distancing could last into 2022, Harvard researchers say in new study
By
Adriana Navarro, AccuWeather staff writer
Published Apr 17, 2020 9:19 PM EDT
On April 17, the Miami Beach Fire Department showed their appreciation for the community members who stay home in light of the COVID-19 pandemic.
A new study not only suggests what the winter of 2020-2021 could hold in the United States in the age of COVID-19, but also looks at what could happen if there are no measures other than social distancing taken to stop the spread of the illness.
And another outbreak could be possible, even in the summer, researchers behind the study say.
"We find that in the absence of other interventions, this kind of on-again off-again approach we call intermittent social distancing, may have to last into mid-2022," Christine Tedijanto, coauthor of the study, "Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period," told AccuWeather over a Skype interview.
The reasoning, Tedijanto and coauthor Stephen Kissler told AccuWeather, is due to how social distancing affected immunity to the new coronavirus. Tedijanto and Kissler are both researchers at the Harvard T.H. Chan School of Public Health.
"We know that social distancing is crucially important in order to flatten the curve and in order to prevent the collapse of our health care system. But if successful, we also slow infections, and this means that immunity in the population builds up slowly," Tedijanto said. "So when we lift the social distancing measures, many people in the population are still going to be susceptible to the infection, and this can lead to a resurgence in cases once the social distancing measures are lifted."
A sign by the New York City parks department indicates the appropriate measurement for social distancing as pedestrians linger in a field at Fort Greene Park, Tuesday, April 14, 2020, in New York. (AP Photo/John Minchillo)
Intermittent social distancing would mean keeping an eye on the number of cases in the population, and monitoring when to "turn on and turn off," social distancing to prevent health care facilities from being overwhelmed while also allowing immunity in the population to grow. The switch would be more of a rolling change than an automatic one.
"The intermittent social distancing scenarios allow us to do exactly this -- to build immunity while maintaining enough social distancing to ensure that everyone receives the hospital care they need," Kissler told AccuWeather in an email. He acknowledged that strong long-term social distancing with a timeframe of 20 weeks, while it wouldn't help a population build up immunity, could buy time to increase hospital capacities and develop treatments. The study is not endorsing a policy, he said, but instead trying to identify likely trajectories of the epidemic under different approaches.
But how reasonable is social distancing for another two years?
"To be clear, 'building population immunity' is a byproduct of widespread infection, not a strategy in and of itself," associate professor of biology at Penn State University Matthew Ferrari told AccuWeather via email. "In order for that many people to develop immunity naturally implies that many people will become ill and may die. Physical distancing is a strategy to slow the rate at which people become sick to guarantee that we have the health system capacity to ensure a good prognosis for all patients."
SARS-CoV-1 (SARS), the virus that infected more than 8,000 and killed 774 in 2003, Ferrari said, was contained not because of immunity, but through "aggressive program of surveillance, contact tracing and isolation."
"The lesson to learn is that, if we want to eliminate this virus, we need to invest in the public health systems that will make that happen," Ferrari said, adding that physical distancing measures have been successfully slowing the spread of the virus, though continuing to do so into 2022 might be a stretch.
A woman wears a lot of face protection as she walks along a street in London, as the country is in lockdown to help curb the spread of the coronavirus, Wednesday, April 15, 2020. The highly contagious coronavirus has impacted nations around the globe, many imposing self isolation and exercising social distancing when people move from their homes. (AP Photo/Frank Augstein)
"The idea of having to go through this longer, or again in the future, is pretty unpalatable," Ferrari said. "The best way to avoid that is to build the health systems that will allow easy, ideally free, access to testing and care in the future. If we can test and identify cases, and trace their contacts and support humane quarantine, then we can focus control on those at risk rather than rely on physical distancing that puts the burden on the healthy."
As pharmaceutical companies race to create a vaccine, the duration of a population's immunity to the virus is a "key factor" in determining the frequency the virus will cause wintertime outbreaks, Tedijanto said.
"If the immunity is on the order of a year like the common cold virus, then perhaps you would expect to see yearly outbreaks in the wintertime," Tedijanto said. "If it's a little bit longer, then perhaps those outbreaks are bi-annual or even more sporadic."
If immunity to the virus falls within this timeline, once the vaccine is developed, people could be going in for their flu shots along with shots for the new coronavirus.
The study found that recurrent wintertime outbreaks of the new coronavirus are likely if the immunity built up to the virus lasts 1-2 years. Immunity in the population to other human coronaviruses that circulate and cause the common cold also generally align with this timeframe, according Kissler. Immunity to SARS and MERS, Tedijanto said, was more on the order to 2-3 years.
"For many viral diseases, including coronaviruses and influenza, transmission is easiest in the winter. This is probably due to both human behavior and to climate factors," Kissler said.
For example, the survival of the influenza virus outside the human body is related to humidity, Kissler said. Typically, these viruses can survive longer in environments with low humidity and low temperatures. The same is true for SARS-CoV-1. An example he gave of human behavior affecting transmission in the winter was more indoor crowding during the colder months.
"Even if SARS-CoV-2 is less transmissible in the summer, though, there are enough susceptible people in the population that a major outbreak will still likely occur," Kissler said.
In a transmission model of SARS-CoV-2, the study found a "substantial outbreak" could occur during any season of the year. However, the transition from winter to spring favored outbreaks with lower peaks while the transition from fall to winter led to more acute outbreaks.
For this reason, researchers say timing the rollback on any social distancing measures should factor in the time of year.
"Once measures are lifted, we unfortunately might see a resurgence in cases," Tedijanto said. "And this could be particularly worrisome in the case of a longer term measure, if our lifting of the measure coincides with the fall or the winter when the virus is more able to spread, so this timing in lifting the measures could lead to a rise in the coronavirus cases that occurs during the fall and winter."
CLICK HERE FOR THE FREE ACCUWEATHER APP
Based on the recommendation of a team of experts, President Donald Trump announced Thursday that states will begin opening the country, "one careful step at a time." The state governors will have the ability to take a "phased and deliberate approach" to re-opening their state depending on their state's circumstances. The reopening of the states will take a rolling approach rather than all at once, but it already looks to be on the horizon. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said some states have already reached a point where they will be able to begin phase one of re-opening.
Companies are also looking toward how to phase workers back into the office environment safely. In a post on Thursday, Facebook CEO Mark Zuckerberg outlined that his company would require the vast majority of its employees to work from home through the end of May at the latest.
"We know that most people can't work from home as easily as many of our employees can," Zuckerberg wrote. "We also know that when society does eventually start re-opening, it will have to open slowly in staggered waves to make sure that the people who are returning to work can do so safely and that we can minimize the possibility of future outbreaks."
In the same post, Zuckerberg wrote Facebook is canceling any large physical events that it had planned with 50 or more people through June of 2021.
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Social distancing could last into 2022, Harvard researchers say in new study
By Adriana Navarro, AccuWeather staff writer
Published Apr 17, 2020 9:19 PM EDT
On April 17, the Miami Beach Fire Department showed their appreciation for the community members who stay home in light of the COVID-19 pandemic.
A new study not only suggests what the winter of 2020-2021 could hold in the United States in the age of COVID-19, but also looks at what could happen if there are no measures other than social distancing taken to stop the spread of the illness.
And another outbreak could be possible, even in the summer, researchers behind the study say.
"We find that in the absence of other interventions, this kind of on-again off-again approach we call intermittent social distancing, may have to last into mid-2022," Christine Tedijanto, coauthor of the study, "Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period," told AccuWeather over a Skype interview.
The reasoning, Tedijanto and coauthor Stephen Kissler told AccuWeather, is due to how social distancing affected immunity to the new coronavirus. Tedijanto and Kissler are both researchers at the Harvard T.H. Chan School of Public Health.
"We know that social distancing is crucially important in order to flatten the curve and in order to prevent the collapse of our health care system. But if successful, we also slow infections, and this means that immunity in the population builds up slowly," Tedijanto said. "So when we lift the social distancing measures, many people in the population are still going to be susceptible to the infection, and this can lead to a resurgence in cases once the social distancing measures are lifted."
A sign by the New York City parks department indicates the appropriate measurement for social distancing as pedestrians linger in a field at Fort Greene Park, Tuesday, April 14, 2020, in New York. (AP Photo/John Minchillo)
Intermittent social distancing would mean keeping an eye on the number of cases in the population, and monitoring when to "turn on and turn off," social distancing to prevent health care facilities from being overwhelmed while also allowing immunity in the population to grow. The switch would be more of a rolling change than an automatic one.
"The intermittent social distancing scenarios allow us to do exactly this -- to build immunity while maintaining enough social distancing to ensure that everyone receives the hospital care they need," Kissler told AccuWeather in an email. He acknowledged that strong long-term social distancing with a timeframe of 20 weeks, while it wouldn't help a population build up immunity, could buy time to increase hospital capacities and develop treatments. The study is not endorsing a policy, he said, but instead trying to identify likely trajectories of the epidemic under different approaches.
But how reasonable is social distancing for another two years?
"To be clear, 'building population immunity' is a byproduct of widespread infection, not a strategy in and of itself," associate professor of biology at Penn State University Matthew Ferrari told AccuWeather via email. "In order for that many people to develop immunity naturally implies that many people will become ill and may die. Physical distancing is a strategy to slow the rate at which people become sick to guarantee that we have the health system capacity to ensure a good prognosis for all patients."
SARS-CoV-1 (SARS), the virus that infected more than 8,000 and killed 774 in 2003, Ferrari said, was contained not because of immunity, but through "aggressive program of surveillance, contact tracing and isolation."
"The lesson to learn is that, if we want to eliminate this virus, we need to invest in the public health systems that will make that happen," Ferrari said, adding that physical distancing measures have been successfully slowing the spread of the virus, though continuing to do so into 2022 might be a stretch.
A woman wears a lot of face protection as she walks along a street in London, as the country is in lockdown to help curb the spread of the coronavirus, Wednesday, April 15, 2020. The highly contagious coronavirus has impacted nations around the globe, many imposing self isolation and exercising social distancing when people move from their homes. (AP Photo/Frank Augstein)
"The idea of having to go through this longer, or again in the future, is pretty unpalatable," Ferrari said. "The best way to avoid that is to build the health systems that will allow easy, ideally free, access to testing and care in the future. If we can test and identify cases, and trace their contacts and support humane quarantine, then we can focus control on those at risk rather than rely on physical distancing that puts the burden on the healthy."
As pharmaceutical companies race to create a vaccine, the duration of a population's immunity to the virus is a "key factor" in determining the frequency the virus will cause wintertime outbreaks, Tedijanto said.
"If the immunity is on the order of a year like the common cold virus, then perhaps you would expect to see yearly outbreaks in the wintertime," Tedijanto said. "If it's a little bit longer, then perhaps those outbreaks are bi-annual or even more sporadic."
If immunity to the virus falls within this timeline, once the vaccine is developed, people could be going in for their flu shots along with shots for the new coronavirus.
The study found that recurrent wintertime outbreaks of the new coronavirus are likely if the immunity built up to the virus lasts 1-2 years. Immunity in the population to other human coronaviruses that circulate and cause the common cold also generally align with this timeframe, according Kissler. Immunity to SARS and MERS, Tedijanto said, was more on the order to 2-3 years.
"For many viral diseases, including coronaviruses and influenza, transmission is easiest in the winter. This is probably due to both human behavior and to climate factors," Kissler said.
For example, the survival of the influenza virus outside the human body is related to humidity, Kissler said. Typically, these viruses can survive longer in environments with low humidity and low temperatures. The same is true for SARS-CoV-1. An example he gave of human behavior affecting transmission in the winter was more indoor crowding during the colder months.
"Even if SARS-CoV-2 is less transmissible in the summer, though, there are enough susceptible people in the population that a major outbreak will still likely occur," Kissler said.
In a transmission model of SARS-CoV-2, the study found a "substantial outbreak" could occur during any season of the year. However, the transition from winter to spring favored outbreaks with lower peaks while the transition from fall to winter led to more acute outbreaks.
For this reason, researchers say timing the rollback on any social distancing measures should factor in the time of year.
"Once measures are lifted, we unfortunately might see a resurgence in cases," Tedijanto said. "And this could be particularly worrisome in the case of a longer term measure, if our lifting of the measure coincides with the fall or the winter when the virus is more able to spread, so this timing in lifting the measures could lead to a rise in the coronavirus cases that occurs during the fall and winter."
CLICK HERE FOR THE FREE ACCUWEATHER APP
Based on the recommendation of a team of experts, President Donald Trump announced Thursday that states will begin opening the country, "one careful step at a time." The state governors will have the ability to take a "phased and deliberate approach" to re-opening their state depending on their state's circumstances. The reopening of the states will take a rolling approach rather than all at once, but it already looks to be on the horizon. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said some states have already reached a point where they will be able to begin phase one of re-opening.
Companies are also looking toward how to phase workers back into the office environment safely. In a post on Thursday, Facebook CEO Mark Zuckerberg outlined that his company would require the vast majority of its employees to work from home through the end of May at the latest.
"We know that most people can't work from home as easily as many of our employees can," Zuckerberg wrote. "We also know that when society does eventually start re-opening, it will have to open slowly in staggered waves to make sure that the people who are returning to work can do so safely and that we can minimize the possibility of future outbreaks."
In the same post, Zuckerberg wrote Facebook is canceling any large physical events that it had planned with 50 or more people through June of 2021.
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