As the Delta variant becomes more prevalent — and its severity better understood — public health authorities look to apply lessons from earlier waves of the COVID-19 pandemic to help curb the recent rise in cases. The latest rise could prompt the return of mask mandates and lockdowns, while leaders continue to emphasize the need for widespread vaccination.
Booster Shots for the Immunocompromised?
The Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP) met this week to discuss whether or not those who have weakened immune systems should get a third dose of the vaccine. Ultimately, the panelists did not make an official recommendation, citing need to further review data, but they advised individuals who are immunocompromised to continue to practice social distancing and masking practices. The U.S. Food and Drug Administration (FDA) is the agency that must authorize the use of a booster shot, and it has not done so.
Olympics Get Underway Amid Rise in Cases; NFL Incentivizes Player Vaccination
The 2020 Tokyo Olympics — postponed last year due to the pandemic — will commence this evening. Dozens of athletes have had to pull out of the event after testing positive for COVID-19. Japan, the host country for the Olympics, is already facing a rise in cases. Only a third of Japan’s population has been vaccinated with one dose, and many are protesting against the events from proceeding. In addition, this week the National Football League (NFL) sent a memo to teams stating if an outbreak caused by unvaccinated players forces the league to cancel a game, and that game cannot be rescheduled, the team with the outbreak will forfeit — and will be deemed to have lost that game. This is the strongest signal a professional sports corporation has made to pressure unvaccinated players to get the vaccine. More than 75% of NFL players are at least partially vaccinated, and more than half of the league's teams have player vaccination rates above 80%.
Pediatricians Recommend Masks for Kids in Schools
This week, the American Academy of Pediatrics recommended all children — regardless of vaccination status — wear masks in school this fall. The CDC is not considering revisiting mask guidance for fully vaccinated school children.
A Return of Mask Mandates?
With COVID-19 infections on the rise and the more contagious Delta variant accounting for 83% of new cases in the U.S., public health authorities are recommending reinstating mask mandates to help curb the spread. Despite guidance from the CDC stating that fully vaccinated individuals do not need to wear masks while indoors, some local communities across the country are urging their residents to wear masks indoors regardless of vaccination status — and in some cases have reinstated or are considering an indoor mask mandate.
Masks 101: How Does a Piece of Cloth Protect Against COVID-19?
The use of masks to combat the spread of COVID-19 has been a hotly debated and politicized topic throughout the pandemic and is once again coming into the spotlight as new mask mandates are being considered. Here are some common questions and answers to why wearing a mask is effective in reducing infections:
- Isn't the SARS-CoV2 virus small enough to pass through a mask? Yes, but the masks are still effective since the virus "travels" through the air as part of a larger particle. The virus particle itself is only about 0.125 microns in size but in order to remain viable and infectious, the virus particle needs to surrounded by water, which carries the virus through the air in aerosolized droplets. These droplets are much larger in size and can be effectively stopped by certain masks. While the most effective mask is the N95 mask (which has a pore size of 0.3 microns), masks comprised of multiple layers of cloth have been shown to effectively block large droplets (20-30 microns), a high percentage of aerosols (droplets and particles smaller than 10 microns) and in some cases fine particles smaller than 1 micron. Besides "size-based" filtration, certain materials in masks may provide electrostatic filtration properties that attract virus particles like a magnet (and may be water repellant). It should be noted that even while wearing a N95 mask, oxygen and carbon dioxide molecules can freely flow in and out of the mask, as both of these molecules are approximately 0.0003 microns wide — or 1000 times smaller than the pore size of an N95 mask.
- Is there any evidence that masks slow COVID-19 infection? Yes, observations and epidemiological studies have concluded that masks are effective in reducing the spread of COVID-19. The CDC has summarized the findings from some of these studies in its Science Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2. There has also been a study reported in PLosOne that demonstrated that a high rate of adherence to a mask mandate in Victoria, Australia, resulted in a significant reduction of COVID-19 cases.
Can Previous Surges Help Us Combat the Delta Variant?
With the highly infectious Delta variant now prevalent in many countries, lessons from previous surges can help countries, states and communities reduce transmission and death. One retrospective study used a number of different data sources — including recorded deaths, PCR and serological testing, hospital occupancy and patient reported outcomes — to recreate COVID epidemic waves across all of England in 2020. The study confirmed the vulnerability of older adults to severe impacts of COVID, and in particular the high transmissibility of the disease in care homes, even with complete restrictions on visiting. The study also suggests that an initial countrywide lockdown, just a week earlier, would have reduced deaths across the entire region by roughly one half. Further, even with high transmission and infection, overall immunity by end of the year was low, and thus only large-scale vaccination uptake, including young people and children, would help reduce infection rates and reduce the need for non-pharmaceutical interventions.
The Importance of Vaccination — and Taking Stock of Losses
A recent study highlighted the importance of large-scale, equitable global vaccination and prevention measures — and included sobering findings about children losing primary caregivers due to COVID-19. The study found that from March 2020 to April 2021, about 1.1 million children lost their primary caregivers — including at least one parent or grandparent — and about 1.5 million children lost at least one primary or secondary caregiver to death from COVID-19. The study included data from the 21 countries that accounted for a majority of global COVID-19 deaths through April 2021. The United States was found to be among the countries with some of the highest numbers of children losing primary caregivers.
Complex and Compounded Medical Needs of Hospitalized and Recovered COVID-19 Patients
A large-scale study of medical complications in more than 80 thousand hospitalized COVID-19 patients examined the wide range of systems affected by the disease. In addition to the respiratory system, which is considered to be the primary target of SARS-CoV-2, the renal, cardiovascular, neurological and gastrointestinal systems were affected significantly by the virus. Another similarly large study documented the “post-COVID-19” medical complications observed up to four months after the initial infection. Data of this type are needed to make informed decisions about the likely demands on the medical systems going forward, and can help in the planning of longer-term health care programs, facilities and related resources.
House Hearing on the Origin of SARS-CoV-2
Two microbiologists testified at a recent U.S. House of Representatives hearing about the origin of SARS-CoV-2. Read this layperson’s summary for a breakdown of the presented positions. You may also watch a the two-hour recording of the full hearing.
What’s Different About Delta Variant?
A published study of the Delta variant indicates that infected individuals become contagious four days after initial exposure (compared to five to seven days for the original variant) and the viral load is about a thousand times higher. Viral load was shown to be the most important single factor in passing the SARS-CoV-2 infection from one individual on to another. Vaccination offers some protection, but in unvaccinated individuals the Delta variant seems to lead to a more severe disease and faster worsening compared to the original variant. Other aspects of the Delta variant and possible future mutations are explored in this 20-minute Nature.com podcast.
Antibiotics Work Against Bacteria — not Viruses
Antibiotics are well established as safe and effective treatments against bacterial infections, but not viruses. A recent study in COVID-19 patients again confirmed this truth for SARS-CoV-2 in a placebo-controlled, randomized clinical trial. The study should be helpful to clinicians considering how to help COVID-19 patients — and knowing what works and what does not. Unlike viruses, bacteria are capable of metabolizing nutrients in order to grow and multiply, and antibiotics often exploit various steps in those metabolic processes to halt bacterial growth and put an end to a bacterial infection. By contrast, viruses do not have an independent capability to use external nutrients, as they lack the necessary molecular machinery, using instead the host cell’s apparatus to produce more viral particles. Nevertheless, in the absence of effective antivirals, especially in a public health crisis, some antibiotics in the past were tried and shown to inhibit replication of some viruses in mice or inside cells grown in a Petri dish, although exact mechanisms remained unclear, and appropriately controlled clinical trials in humans were lacking. Current World Health Organization (WHO) guidelines include a warning against the inappropriate use of antibiotics, because their overuse may lead to the emergence of antibiotic-resistant bacteria, and therefore is not harmless.