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October 2nd, 2020


In addition to the regular review of recent scientific developments surrounding COVID-19, this week’s newsletter brings a deeper exploration of singing. Many schools and churches have halted singing during the pandemic. The volume of evidence surrounding singing is growing and we are now able to make some more evidence based recommendations. Also, thank you for spreading the word about this newsletter. We are very appreciative of your recommendations and encourage you to pass this newsletter along to anyone who may benefit from the information.

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Children and COVID-19

Two interesting articles were published within the past week with slightly differing conclusions. The first article was published in JAMA Pediatrics which reviewed all the published literature through July 28th, 2020 on children and COVID-19 in order to answer a few key questions. The review concluded that there was “preliminary evidence that children and adolescents have lower susceptibility to SARS-CoV-2” and that “there is weak evidence that children and adolescents play a lesser role than adults in transmission of SARS-CoV-2 at a population level.” It also stated the “study provides no information on the infectivity of children.”

Another publication this week in the journal Science reviewed a very large database of contact tracing information from India, involving 575,071 individuals exposed to 84,965 confirmed cases. They were able to make several important conclusions:

  •  “High prevalence of infection among children who were contacts of cases around their own age”. This was also present for adults. It means that people who tested positive  (in India) were more likely to pass it along to others their same age.
  • Children have better outcomes than adults. The population that did best was in the 5-17 age group, followed closely by those 0-4 and 18-29. Otherwise, severity increased in a linear fashion with age.

Overall, both studies confirm what we know. Children can become infected but have very good outcomes the vast majority of the time. Additionally, they are capable of infecting others. So mitigation strategies like masks, distancing, ventilation, etc. are all very important, even for children.

Herd Immunity

You have likely read about heard immunity. It occurs when most of the population is immune to a disease, whether from vaccination or infection and recovery. It is an important strategy in combating an infection that poses a risk to the general public. Achieving herd immunity requires that 50-90% of the population be immune. Estimates depend on the infection and how easily it is transmitted. It is believed we will require 70% immunity for COVID-19. A study from Stanford University was published this week in the journal Lancet. It randomly sampled 28,503 adult dialysis patients throughout the U.S. for antibodies to COVID-19. They found an overall average of 9% immunity in this population. They also noted that those living in more population dense areas, those in the the northeast, and those from primarily Hispanic and Black neighborhoods had the highest levels of immunity. At maximum, 27% of those living in the northeast were immune. That is significantly less than the 50-70% needed for herd immunity nationally.

NAS and NAM letter

The U.S. National Academies of Science, Engineering, and Medicine represent organizations that have provided valuable input on all scientific matters from an independent, non-governmental perspective that is outside the influence of typical national politics. The academies of Science and Medicine jointly released a statement against the current climate of political interference in science during the pandemic.

New York Cases Increasing

This past week brought a slight increase in the number of cases in New York City for the first time since the early days of the pandemic. There was one day when the case positivity increased to 3.2%. It is important to remember the goal for the city is less than 3% averaged over 7 days, and the goal for the state is less than 5% averaged over 14 days. Thankfully, the daily case positivity decreased later in the week, but there have been reports about local outbreaks. Continued vigilance in all safety measures is critical. You can track daily statistics on our New York Covid-19 Dashboard (login required).

New York International Travel Advisory

Governor Cuomo issued an executive order for international travelers coming into New York State. “The advisory requires individuals who have traveled to New York from areas with significant community spread (of COVID) to quarantine for 14 days. The quarantine applies to any person arriving from an area with a positive test rate higher than 10 per 100,000 residents over a 7-day rolling average or an area with a 10 percent or higher positivity rate over a 7-day rolling average.“ The order was signed on 09/29/20 and mirrors the mandatory quarantine for travelers to U.S. states with similar disease transmission levels. International travel was previously not discussed in the New York travel advisory and many questions from parents and schools in New York were submitted on this subject. This order now aligns the recommendations for all travel outside the state.

Florida Moves To Phase 3

Governor DeSantis issued an executive order on Sept 25th moving Florida into phase 3 of the reopening plan. The order indicates that restaurants may now open at full capacity and cannot be restricted to less than 50% by local ordinance. It also suspends the collection of fines and penalties associated with COVID-19 enforced upon individuals. Though this will effect local ordinance and mask use requirements throughout the state, it does not specifically mention schools and it does not prevent any school from continuing to use all of the COVID-19 mitigation strategies we recommend. Public and private schools in the state continue to require measures such as masks, symptom screening, and distancing, without change. Phase 3 is the final phase described in the governor’s plan for state reopening.

Vitamin D

A recent publication suggests an association between vitamin D and improved outcomes in COVID-19. Of 235 patients hospitalized with COVID-19, 9.7% of those over 40 with adequate vitamin D levels died, while 20% of those with low levels died. Though this suggests an association between the two, it is important to remember that these types of studies do not prove causation. That means we can not say that more people died of COVID-19 because of the vitamin D deficiency. It is safe to take vitamin D supplements daily, especially if directed to do so by your doctor, and it may help if you are hospitalized with COVID-19. However, vitamins are not harmless. If you choose to take a supplement, please do not exceed the daily allowance of vitamin D.


Since the discovery of SARS-CoV-2 in respiratory droplets and the early reports of large COVID outbreaks in choirs, singing has been considered a dangerous activity. However, a few organizations and authors have taken the time to study and publish investigations of singing and instrument use, resulting in sufficient evidence to begin making some recommendations.

Before we get to those recommendations, lets review some of what the science tells us:

  • The virus is known to be present in droplets.
  • Talking, coughing, sneezing, and singing have been found to spray considerable droplets of all sizes. Talking releases the least.
  • Smaller size droplets linger in the air for longer periods of time and travel farther.
  • The virus can survive on surfaces for different periods of time after being aerosolized.
  • Droplet and aerosol production has been shown to greatly decrease when wearing a mask. In fact, this remains the best safety measure we have available.
  • Aerosol production of masked singing has been shown to be equivalent to speaking.
  • Volume matters. This means quiet singing sprays less droplets than louder singing.
  • Certain consonants like “B” and “P” release more droplets.
  • “Super spreaders” or those people who release large quantities of infectious virus in their droplets, are the minority. However, they are also responsible for occurrences where large quantities of people get infected in a short time.

With those details, some recommendations can be made:

  • Singing may occur if masks and appropriate distance are maintained.
  • Appropriate distancing for singing, especially without masks, is likely to be over 12 feet. With masks use, this distance can be closer to the 6 feet recommended for speech. Keep in mind there may be state regulations requiring more distance, for example: the New York State Dept Of Health guidelines for prek-12 schools require a minimum distance of 12 feet between students for singing activities.
  • Ventilation matters. Outdoor moving air is the safest. If you are going to sing indoors you need to do some work first.
    • Calculate your air changes per hour for the room. This is calculated by measuring the dimensions of the room, including ceiling height, and knowing your HVAC changes per minute (CPM) rating. There is a free online calculator and summary here form an HVAC dealer.
    • You need at least 6 air changes to get 99% efficiency filtration. This is the medical standard. ASHRAE suggests 2 air changes here. Depending on your system and room size, this may take up to an hour after a singing session. One study recommended at least 30 minutes between sessions.
    • Your HVAC system should have at least a MERV 13 filter to be effective at removing 85% of SARS-CoV-2. But use of HEPA filters, in the system or in free standing units, improves filtration and reduces time.
  • Singing time matters. Limit the duration to as short a time period as possible, preferably less than 30 minutes.
  • High risk activities should be limited to those at lowest risk. Those with multiple medical problems or high risk characteristics should avoid these activities and alternative activities should be provided for them if in school.
  • No shields. Though we have spoken about the use of shields for those who have a medical reason not to wear a mask, this is one of those activities where these people should be excluded. Not only is a shield inadequate in this scenario, but it also places the remainder of the singers at higher risk of being infected by the person wearing the shield.

So, singing is certainly possible. Most schools and businesses have already assembled the required information to make the air changes per hour calculation and have taken the appropriate HVAC mitigation steps. All that remains is putting it together to form a singing protocol.

A few helpful resources:

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