2/17—Israel: 94% drop in symptomatic COVID-19 infections in 600,000 people with 2 doses of Pfizer vaccine
Israeli study finds 94% drop in symptomatic COVID-19 cases with Pfizer vaccine
[Media report.] Israel’s largest healthcare provider on Sunday reported a 94% drop in symptomatic COVID-19 infections among 600,000 people who received two doses of the Pfizer’s vaccine in the country’s biggest study to date. Health maintenance organization Clalit, which covers more than half of all Israelis, said the same group was also 92% less likely to develop severe illness from the virus. The comparison was against a group of the same size, with matching medical histories, who had not received the vaccine.
COVID-19 Vaccination in Pregnant and Lactating Women
Given what is known about the COVID-19 vaccines, the limited data regarding COVID-19 vaccines in pregnant and lactating women from those who have been immunized, and use of other vaccines during pregnancy, physicians can empower women to make an informed decision. With an understanding of the important practice of vaccination in pregnancy, the use of other vaccines during pregnancy, the efficacy and safety of COVID-19 mRNA vaccines in nonpregnant populations, and their mechanism of inducing an immune response, clinicians can outline the benefit of prevention of COVID-19 illness, as well as the undefined but possibly limited risk to the fetus, and potential benefit to the neonate. As part of the discussion, clinicians should acknowledge with empathy the limited available evidence, as well as the tension over the potential benefits of vaccination weighed against the potential risks—whether real or theoretical—and be prepared to dispel myths.
To Increase Confidence in COVID-19 Vaccines, Decision-Makers Need to Showcase Public Support, Leverage Endorsements, Focus on Hesitant Individuals, and Engage Communities
[National Academies report.] Decision-makers leading COVID-19 vaccine rollouts need to begin communicating with the public immediately if they have not already — emphasizing public support for vaccinations, leveraging celebrity and community champion endorsements, and focusing on those who are skeptical or hesitant of the vaccines rather than firmly opposed — to ensure demand and promote uptake, says a new rapid expert consultation from the National Academies of Sciences, Engineering, and Medicine. [See also full report.]
Effectiveness of Mask Wearing to Control Community Spread of SARS-CoV-2
Compelling data now demonstrate that community mask wearing is an effective nonpharmacologic intervention to reduce the spread of this infection, especially as source control to prevent spread from infected persons, but also as protection to reduce wearers’ exposure to infection. At a hair salon in which all staff and clients were required to wear a mask under local ordinance and company policy, 2 symptomatic, infected stylists attended to 139 clients and no infections were observed in the 67 clients who were reached for interviewing and testing. During a COVID-19 outbreak on the USS Theodore Roosevelt, persons who wore masks experienced a 70% lower risk of testing positive for SARS-CoV-2 infection. Similar reductions have been reported in case contact investigations when contacts were masked and in household clusters in which household members were masked. A study that examined changes in growth rates for infections in 15 states and the District of Columbia before and after mask mandates showed that rates were growing before the mandates were enacted and slowed significantly after, with greater benefit the longer the mandates had been in place.
Genetic Variants of SARS-CoV-2—What Do They Mean?
There is intense interest in whether mutations in the spike glycoprotein mediate escape from host antibodies and could potentially compromise vaccine effectiveness, since spike is the major viral antigen in the current vaccines. At this point, strong selection of a variant at the population level is probably not driven by host antibody because there are not sufficient numbers of immune individuals to systematically push the virus in a given direction. In contrast, if a variant has one or more mutations in spike that increase transmissibility, it could quickly outcompete and replace other circulating variants. Because current vaccines provoke an immune response to the entire spike protein, it is hoped that effective protection may still occur despite a few changes at antigenic sites in SARS-CoV-2 variants. Regardless of why the mutations were selected, it is reasonable to expect that many mutations in spike might affect neutralization by convalescent sera. It is therefore important to consider both the magnitude of the change in neutralization and the number of serum samples evaluated. Another issue is that viral glycoproteins are subject to evolutionary trade-offs. Sometimes a mutation that enhances one viral property, such as binding to a receptor, can reduce another property, such as escaping host antibody. Indeed, recent evidence suggests this could be the case for D614G. It is possible that mutations in spike that are “good” for the virus right now could also make it less fit in the context of population-level immunity in the future.