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After initially containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many European and Asian countries had a resurgence of COVID-19 consistent with a large proportion of the population remaining susceptible to the virus after the first epidemic wave.1Lucy CO Verity R Watson OJ et al.Have deaths from COVID-19 in Europe plateaued due to herd immunity?.Lancet. 2020; 395: e110-e111Summary Full Text Full Text PDF Scopus (11) Google Scholar By contrast, in Manaus, Brazil, a study of blood donors indicated that 76% (95% CI 67–98) of the population had been infected with SARS-CoV-2 by October, 2020.2Buss LF Prete CA Abrahim CMM et al.Three-quarters attack rate of SARS-CoV-2 in the Brazilian Amazon during a largely unmitigated epidemic.Science. 2020; 371: 288-292Crossref Google Scholar High attack rates of SARS-CoV-2 were also estimated in population-based samples from other locations in the Amazon Basin—eg, Iquitos, Peru 70% (67–73).3Álvarez-Antonio C Meza-Sánchez G Calampa C et al.Seroprevalence of anti-SARS-CoV-2 antibodies in Iquitos, Loreto, Peru.MedRxiv. 2021; (published online 20.) (preprint)https://doi.org/10.1101/2021.01.17.21249913Google Scholar The estimated SARS-CoV-2 attack rate in Manaus would be above the theoretical herd immunity threshold (67%), given a basic case reproduction number (R0) of 3.4

BackgroundEfficacious vaccines are urgently needed to contain the ongoing coronavirus disease 2019 (Covid-19) pandemic of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A candidate vaccine, Ad26.COV2.S, is a recombinant, replication-incompetent adenovirus serotype 26 (Ad26) vector encoding a full-length and stabilized SARS-CoV-2 spike protein. MethodsIn this multicenter, placebo-controlled, phase 1–2a trial, we randomly assigned healthy adults between the ages of 18 and 55 years (cohort 1) and those 65 years of age or older (cohort 3) to receive the Ad26.COV2.S vaccine at a dose of 5×1010 viral particles (low dose) or 1×1011 viral particles (high dose) per milliliter or placebo in a single-dose or two-dose schedule. Longer-term data comparing a single-dose regimen with a two-dose regimen are being collected in cohort 2; those results are not reported here. The primary end points were the safety and reactogenicity of each dose schedule. ResultsAfter the administration of the first vaccine dose in 805 participants in cohorts 1 and 3 and after the second dose in cohort 1, the most frequent solicited adverse events were fatigue, headache, myalgia, and injection-site pain. The most frequent systemic adverse event was fever. Systemic adverse events were less common in cohort 3 than in cohort 1 and in those who received the low vaccine dose than in those who received the high dose. Reactogenicity was lower after the second dose. Neutralizing-antibody titers against wild-type virus were detected in 90% or more of all participants on day 29 after the first vaccine dose (geometric mean titer [GMT], 224 to 354) and reached 100% by day 57 with a further increase in titers (GMT, 288 to 488), regardless of vaccine dose or age group. Titers remained stable until at least day 71. A second dose provided an increase in the titer by a factor of 2.6 to 2.9 (GMT, 827 to 1266). Spike-binding antibody responses were similar to neutralizing-antibody responses. On day 14, CD4+ T-cell responses were detected in 76 to 83% of the participants in cohort 1 and in 60 to 67% of those in cohort 3, with a clear skewing toward type 1 helper T cells. CD8+ T-cell responses were robust overall but lower in cohort 3. ConclusionsThe safety and immunogenicity profiles of Ad26.COV2.S support further development of this vaccine candidate. (Funded by Johnson & Johnson and the Biomedical Advanced Research and Development Authority of the Department of Health and Human Services; COV1001 ClinicalTrials.gov number, NCT04436276. opens in new tab.)

More than 200 COVID-19 vaccines are in development worldwide, with governments securing deals to access advance doses. But access is only one issue. Willingness to accept a COVID-19 vaccine when it becomes available has varied considerably across countries over the course of the pandemic. In The Lancet Infectious Diseases, we presented data collected in Australia in April, 2020,1Dodd RH Cvejic E Bonner C Pickles K McCaffery K Willingness to vaccinate against COVID-19 in Australia.Lancet Infect Dis. 2020; (published online June 30.)https://doi.org/10.1016/S1473-3099(20)30559-4Summary Full Text Full Text PDF PubMed Scopus (8) Google Scholar which suggested 86% of people surveyed (3741 of 4362) would be willing to vaccinate against COVID-19 if a vaccine became available. Furthermore, the COCONEL group2The COCONEL GroupA future vaccination campaign against COVID-19 at risk of vaccine hesitancy and politicisation.Lancet Infect Dis. 2020; 20: 769-770Summary Full Text Full Text PDF PubMed Scopus (18) Google Scholar showed in March, 2020, that 74% of French citizens would vaccinate. Between April and July, 2020, willingness to vaccinate has ranged from 58% in the USA3Fisher KA Bloomstone SJ Walder J Crawford S Fouayzi H Mazor KM Attitudes toward a potential SARS-CoV-2 vaccine: a survey of US adults.Ann Intern Med. 2020; (published online Sept 4.)https://doi.org/10.7326/M20-3569Crossref Google Scholar to 64% in the UK4Sherman S Smith L Sim J et al.COVID-19 vaccination intention in the UK: results from the COVID-19 Vaccination Acceptability Study (CoVAccS), a nationally representative cross-sectional survey.medRxiv. 2020; (published online Aug 14.) (preprint, version 1)https://doi.org/10.1101/2020.08.13.20174045Google Scholar and 74% in New Zealand.5Menon RGV Thaker J Aotearoa-New Zealand public attitudes to COVID-19 vaccine.https://mro.massey.ac.nz/handle/10179/15567Date: Aug 20, 2020Google Scholar The New Zealand data showed that the most commonly reported reasons to get vaccinated were to protect family and self, with safety being the chief concern about the vaccine. It is important to investigate both motivations and concerns about a future COVID-19 vaccine to help shape communication strategies.

BackgroundA safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials.MethodsThis analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674.FindingsBetween April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0–75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4–97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8–80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3–4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation.InterpretationChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials.

If asked, many scientists would probably agree with the statement ‘Natural infection gives better immunity than vaccination’. Indeed, if one survives the infection, there are certainly many pathogens for which natural infection induces stronger immune responses and more long-lived immunity than does vaccination. Measles is prototypic of this1. While there was a clear risk, after infection, of death, encephalitis and pneumonia before there was a vaccine, survivors gained lifelong immunity. Vaccination against measles, on the other hand, requires two shots and may not offer lifelong complete protection but has proven to be good enough to keep the disease in check when widely implemented.

We study the role of social connections in compliance of U.S. households with mobility restrictions imposed in response to the coronavirus disease 2019 (COVID-19) pandemic, using aggregated and anonymized Facebook data on social connections and mobile phone data for measuring social distancing at the county level. Relative to the average restriction efficacy, a county with one-SD more social connections with China and Italy—the first countries with major COVID-19 outbreaks—has a nearly 50% higher compliance with mobility restrictions. By contrast, social connections of counties with less-educated populations, a higher Trump vote share, and a higher fraction of climate change deniers show decreased compliance with mobility restrictions. Our analysis suggests that social connections are conduits of information about the pandemic and an economically important factor affecting compliance with, and impact of, mobility restrictions

Global efforts for development of a COVID-19 vaccine are yielding multiple results including some new and as yet unlicensed technologies.1Le TT Cramer JP Chen R Mayhew S Evolution of the COVID-19 vaccine development landscape.Nat Rev Drug Discov. 2020; 19: 667-668Crossref PubMed Scopus (17) Google Scholar Reception of these vaccine candidates by a skeptical public will challenge wide acceptance of new vaccines. Regulatory safety thresholds are a minimum bar that a product must pass to attain regulatory approval, but for the general public, cumulative safety experience will be important. Trust is earned with time, and with repeated experience. Vaccines have a long safety history, but COVID-19 vaccines are new. In this context, Yanjun Zhang and colleagues' report of their phase 1/2 trial of a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in The Lancet Infectious Diseases is instructive.2Zhang Y Zheng G Pan H et al.Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine in healthy adults aged 18–59 years: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial.Lancet Infect Dis. 2020; (published online Nov 17.)https://doi.org/10.1016/S1473-3099(20)30843-4Google Scholar

As the COVID-19 pandemic progresses, an understanding of the structure and organization of beliefs in pandemic conspiracy theories and misinformation becomes increasingly critical for addressing the threat posed by these dubious ideas. In polling Americans about beliefs in 11 such ideas, we observed clear groupings of beliefs that correspond with different individual-level characteristics (e.g., support for Trump, distrust of scientists) and behavioral intentions (e.g., to take a vaccine, to engage in social activities). Moreover, we found that conspiracy theories enjoy more support, on average, than misinformation about dangerous health practices. Our findings suggest several paths for policymakers, communicators, and scientists to minimize the spread and impact of COVID-19 misinformation and conspiracy theories.

The Guidance on National Deployment and Vaccination Planning is intended to help countries develop their plan for COVID-19 vaccine introduction.

Scientists now have better tests and treatments, and are forging a clear pathway out of this global ordeal