Efficacy and Safety of NVX-CoV2373 in Adults in the United States and Mexico.

BACKGROUND: NVX-CoV2373 is an adjuvanted, recombinant spike protein nanoparticle vaccine that was shown to have clinical efficacy for the prevention of coronavirus disease 2019 (Covid-19) in phase 2b-3 trials in the United Kingdom and South Africa, but its efficacy had not yet been tested in North America. METHODS: We conducted a phase 3, randomized, observer-blinded, placebo-controlled trial in the United States and Mexico during the first half of 2021 to evaluate the efficacy and safety of NVX-CoV2373 in adults (≥18 years of age) who had not had severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Participants were randomly assigned in a 2:1 ratio to receive two doses of NVX-CoV2373 or placebo 21 days apart. The primary objective was to determine vaccine efficacy against reverse-transcriptase-polymerase-chain-reaction-confirmed Covid-19 occurring at least 7 days after the second dose. Vaccine efficacy against moderate-to-severe disease and against different variants was also assessed. RESULTS: Of the 29,949 participants who underwent randomization between December 27, 2020, and February 18, 2021, a total of 29,582 (median age, 47 years; 12.6% ≥65 years of age) received at least one dose: 19,714 received vaccine and 9868 placebo. Over a period of 3 months, 77 cases of Covid-19 were noted - 14 among vaccine recipients and 63 among placebo recipients (vaccine efficacy, 90.4%; 95% confidence interval [CI], 82.9 to 94.6; P<0.001). Ten moderate and 4 severe cases occurred, all in placebo recipients, yielding vaccine efficacy against moderate-to-severe disease of 100% (95% CI, 87.0 to 100). Most sequenced viral genomes (48 of 61, 79%) were variants of concern or interest - largely B.1.1.7 (alpha) (31 of the 35 genomes for variants of concern, 89%). Vaccine efficacy against any variant of concern or interest was 92.6% (95% CI, 83.6 to 96.7). Reactogenicity was mostly mild to moderate and transient but was more frequent among NVX-CoV2373 recipients than among placebo recipients and was more frequent after the second dose than after the first dose. CONCLUSIONS: NVX-CoV2373 was safe and effective for the prevention of Covid-19. Most breakthrough cases were caused by contemporary variant strains. (Funded by Novavax and others; PREVENT-19 ClinicalTrials.gov number, NCT04611802.).

International travel patterns and travel risks for stem cell transplant recipients.

BACKGROUND: Stem cell transplantation (SCT) is being increasingly utilized for multiple medical illnesses. However, there is limited knowledge about international travel patterns and travel-related illnesses of stem cell transplant recipients (SCTRs). METHODS: An observational cross-sectional study was conducted among 979 SCTRs at Memorial Sloan Kettering Cancer Center using a previously standardized and validated questionnaire. International travel post SCT, pre-travel health advice, exposure risks, and travel-related illnesses were queried. RESULTS: A total of 516 SCTRs completed the survey (55% response rate); of these, 40% were allogeneic SCTRs. A total of 229 (44.3%) respondents reported international travel outside the United States and Canada post SCT. The international travel incidence was 32% [95% confidence interval CI 28-36] within 2 years after SCT. Using multivariable Cox regression analysis, variables significantly associated with international travel within first 2 years after SCT were history of international travel prior to SCT [hazard ratio (HR) = 5.3, 95% CI 2.3-12.0], autologous SCT (HR = 2.6, 95% CI 1.6-2.8), foreign birth (HR = 2.3, 95% CI 1.5-3.3), and high income (HR = 2.0, 95% CI 1.8-3.7). During their first trip, 64 travelers (28%) had traveled to destinations that may have required vaccination or malaria chemoprophylaxis. Only 56% reported seeking pre-travel health advice. Of those who traveled, 16 travelers (7%) became ill enough to require medical attention during their first trip after SCT. Ill travelers were more likely to have visited high-risk areas (60 vs 26%, p = 0.005), to have had a longer mean trip duration (24 vs 12 days, p = 0.0002), and to have visited friends and relatives (69 vs 21%, p < 0.0001). CONCLUSIONS: International travel was common among SCTRs within 2 years after SCT and was mainly to low-risk destinations. Although the overall incidence of travel-related illnesses was low, certain subgroups of travelers were at a significantly higher risk. Pre-travel health counseling and interventions were suboptimal.

American Indian youth substance abuse: community-driven interventions.

Substance abuse among American Indians has a long history that dates back to the colonial era. American Indian youth today continue to have one of the highest substance abuse rates when compared with other groups. Researchers have implemented American Indian youth substance abuse interventions that previously have worked in the general population, but studies have found that they are generally unprepared and poorly designed for American Indian populations. The lack of inclusion of American Indian populations in the interventional studies, poor understanding of American Indian diversity and cultures, and lack of consideration for the unique historical and sociopolitical context of each tribe were cited as reasons the interventions failed. It has been suggested that historical trauma plays a considerable role in American Indian youth substance abuse; however, much of this theoretical framework has yet to be rigorously tested. Contemporary trauma appears to contribute significantly more to American Indian youth substance abuse. The data on American Indian substance abuse are limited, but what is currently available appears to show a vast heterogeneity in the level of substance abuse among American Indian youth that varies across different American Indian tribes and geographical distribution. In summary, this article seeks to describe the special relationship American Indian tribes have with the federal government, review historical and contemporary trauma, review American Indian youth substance abuse and interventions today, and finally describe a unique intervention strategy that tribes in the Pacific Northwest are implementing in order to combat American Indian youth substance abuse.