The Count

Region	Cases	Deaths
World	14,750,032	610,839
US	3,925,886	143,515

Getting to Herd Immunity: Beware of Shortcuts The idea that we can get to herd immunity by allowing the young and less vulnerable to become infected leads to a dangerously flawed strategy. The results could be millions dead, hundreds of thousands chronically ill and a vulnerable population (the elderly and those with underlying health conditions) at risk of explosive outbreaks or forced into perpetual isolation.

Research News

Phase I Trial of mRNA vaccine demonstrates clear, substantial antibody response A trial of 45 adults found that an mRNA vaccine generated high, dose-dependent, antibody titers to SARS-CoV-2 that were amplified by a second vaccine dose. Increased T-cell response was also demonstrated, and, after the second dose, all patients demonstrated neutralization of both a pseudo virus in vivo and a live virus in vitro. These promising results bode well for the potential of this particular vaccine.

Antibody levels begin to decline early in convalescence. Canadian researchers found that IgG levels began a significant decline as soon as 6-10 weeks after infection. This was associated with a significant decline in the ability of convalescent plasma to neutralize pseudo particles containing the SARS-CoV-2 spike protein. The implications of this for the durability of immunity are not clear, but they raise questions that could have major implications for vaccine efficacy and must be carefully investigated.

Six new papers consider efficacy of masks from their impact on particle dispersion to their patterns of usage to their impact on the spread of COVID-19. The results clearly and unequivocally support the effectiveness of all masks and the value of their use to limit respiratory spread of SARS-CoV-2.

Even a used tee shirt blocks most airborne particles A comparison of a range of common fabrics found that all materials dramatically reduce the transmission of particles. Even a single layer of a loosely woven undershirt fabric blocked a median of 73% of particles from reaching a petri dish 30 mm from the fabric, although, on repeat testing, the worst case was only 29% blockage. Three layers of folded undershirt fabric matched the performance of a medical mask.

Larger, wrap-around masks perform better. An analysis of mask designs by the MITRE corporation also found that common fabrics can form effective masks. The study went on to look at mask design and found that small homemade or non-specialty masks do not compare well to surgical masks. For these non-medical grade masks, large, wrap-around masks are more effective.

Mask Use varies widely with age, sex, and location. Investigators in Wisconsin found that females, older individuals, and those in urban and suburban areas are more likely to wear masks in retail stores. The sharpest difference was between suburban areas (49% usage) as compared to rural shoppers (20%). It should be noted that mask usage was relatively low (below 50%) throughout this area of Southeastern Wisconsin during the study period, June 3-June9.

Percent of the population not wearing masks in March strongly predicts country and state COVID-19 death rates. An ecological analysis of COVID-19 death rates over the course of the pandemic found that percent of people not wearing masks was strongly correlated with COVID-19 death rates, both at the country level (r=.72) and for US states (4=.49). This could be the direct result of the protective effect of masks, an indicator of general compliance and caution, or a combination of the two.

Early use of masks might have saved 55,000 lives in the US A pandemic model estimated that a mask mandate in April could have reduced deaths in the US by between 17 and 55% by the end of May. If states that closed non-essential businesses and invoked stay at home orders had not done so, the authors estimated that deaths would have increased by as much as 60% and 170% respectively.

Widespread use of masks could cut resurgence in half Another model projects that the introduction of masks with at least moderate compliance could reduce the current resurgence in cases by 50% or more.

Firearm purchases and firearm violence both rose during the pandemic The pandemic appears to have sparked a sharp increase in firearm purchases in the United States (an estimated excess of 2.1 million weapons), which was followed by a sharp increase in firearm injuries. Although this ecological association is not necessarily causal, it is worrisome.

Pooled samples can reduce the number of tests required by 80% Only 20 samples are required to test 100 people with 1% infected if pooling is used. The efficiency of pooling decreases with increasing infection prevalence, but has advantages over individual testing up to 30% prevalence.

An outbreak in a Chilean school demonstrates involvement of staff and teachers A study of antibody levels at a K-12 school in Santiago following an outbreak in which the index cases appear to have been teachers and/or parents found 10% of students and 17% of staff were seropositive with 18% of adults and 40% of children asymptomatic. This appears to have been an outbreak originating in the adults and later spreading to children. It is difficult to generalize these results to other settings and caution should be exercised in doing so.

Two studies produced apparently contradictory results on the relationship between antibody response and disease severity. A University of Texas study found no association between antibody response and disease severity. A comparison of IgG and IgM levels between ICU admissions and other COVID cases concluded that there was no significant difference between the groups. A UCSF study found sharply higher antibody levels in severe cases (ICU admissions). The reasons for the apparent differences in results between these two studies is not immediately clear and requires further investigation.

Two case studies suggest that SARS-CoV-2 infections have the potential to cause Guillain Barre Syndrome A case in Spain in a 15 year-old and a second case in Saudi Arabia in an eleven-year-old suggest that this neurological syndrome needs to be added to the potential adverse effects of SARS-CoV-2.

Two studies raise concerns about the potential for SARS-CoV-2 to cause a Kawasaki-like syndrome One describing a case in a 45-year-old man in New York indicates the potential for this severe disease to extend beyond the typical pediatric population and a second describing the disease in seven British infants suggests the potential for the occurrence of a particularly aggressive form of the syndrome in the very young.

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*peer reviewed.