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1.
Vaccine ; 2022.
Article in English | ScienceDirect | ID: covidwho-1815247

ABSTRACT

Vaccine effectiveness is lower and wanes faster against infection and symptomatic disease caused by the omicron variant of SARS-CoV-2 than was observed with previous variants. Vaccine effectiveness against severe omicron disease, on average, is higher, but has shown variability, including rapid apparent waning, in some studies. Assessing vaccine effectiveness against omicron severe disease using hospital admission as a measure of severe disease has become more challenging because of omicron’s attenuated intrinsic severity and its high prevalence of infection. Many hospital admissions likely occur among people with incidental omicron infection or among those with infection-induced exacerbation of chronic medical conditions. To address this challenge, the World Health Organization held a virtual meeting on March 15, 2022, to review evidence from several studies that assessed Covid-19 vaccine effectiveness against severe omicron disease using several outcome definitions. Data was shown from studies in South Africa, the United States, the United Kingdom and Qatar. Several approaches were proposed that better characterize vaccine protection against severe Covid-19 disease caused by the omicron variant than using hospitalization of omicron-infected persons to define severe disease. Using more specific definitions for severe respiratory Covid-19 disease, such as indicators of respiratory distress (e.g. oxygen requirement, mechanical ventilation, and ICU admission), showed higher vaccine effectiveness than against hospital admission. Second, vaccine effectiveness against progression from omicron infection to hospitalization, or severe disease, also showed higher vaccine protection. These approaches might better characterize vaccine performance against severe Covid-19 disease caused by omicron, as well as future variants that evade humoral immunity, than using hospitalization with omicron infection as an indicator of severe disease.

2.
PLOS ONE ; 17(4):e0267154-e0267154, 2022.
Article in English | PMC | ID: covidwho-1799046

ABSTRACT

Various efforts to increase COVID-19 vaccination rates have been employed in the United States. We sought to rapidly investigate public reactions to these efforts to increase vaccination, including self-reported responses to widespread reduced masking behavior, monetary incentive programs to get vaccinated, and work vaccination requirements. Using a unique method for data collection (Random Domain Intercept Technology), we captured a large ( N = 14,152), broad-based sample of the United States Web-using population (data collected from June 30 –July 26, 2021). About 3/4 of respondents reported being vaccinated. The likelihood of vaccination and vaccination intention differed across various demographic indicators (e.g., gender, age, income, political leaning). We observed mixed reactions to efforts aimed at increasing vaccination rates among unvaccinated respondents. While some reported that specific efforts would increase their likelihood of getting vaccinated (between 16% and 32%), others reported that efforts would decrease their likelihood of getting vaccinated (between 17% and 42%). Reactions differed by general vaccination intention, as well as other demographic indicators (e.g., race, education). Our results highlight the need to fully understand reactions to policy changes, programs, and mandates before they are communicated to the public and employed. Moreover, the results emphasize the importance of understanding how reactions differ across groups, as this information can assist in targeting intervention efforts and minimizing potentially differential negative impact.

4.
Clin Infect Dis ; 72(3): 515-518, 2021 02 01.
Article in English | MEDLINE | ID: covidwho-1387743

ABSTRACT

While the role of children in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains to be defined, children likely play an important role based on our knowledge of other respiratory viruses. Children are more likely to be asymptomatic or have milder symptoms and less likely to present for healthcare and be tested for SARS-CoV-2. Thus, our current estimates are likely under-representative of the true burden of SARS-CoV-2 in children. Given the potential direct benefit of a SARS-CoV-2 vaccine in children and the substantial indirect benefit through community protection, or "herd immunity," we argue that planning and implementation of SARS-CoV-2 vaccines should include children. Furthermore, community protection occurred after widespread implementation of prior childhood vaccines against Streptococcus pneumoniae, rubella, and rotavirus. We detail considerations for vaccine clinical trials, potential barriers to the implementation of widespread vaccination and argue why children would be an ideal target population for vaccination.


Subject(s)
COVID-19 , Viral Vaccines , COVID-19 Vaccines , Child , Humans , Immunity, Herd , SARS-CoV-2
5.
Vaccine ; 39(30): 4013-4024, 2021 07 05.
Article in English | MEDLINE | ID: covidwho-1253726

ABSTRACT

Phase 3 randomized-controlled trials have provided promising results of COVID-19 vaccine efficacy, ranging from 50 to 95% against symptomatic disease as the primary endpoints, resulting in emergency use authorization/listing for several vaccines. However, given the short duration of follow-up during the clinical trials, strict eligibility criteria, emerging variants of concern, and the changing epidemiology of the pandemic, many questions still remain unanswered regarding vaccine performance. Post-introduction vaccine effectiveness evaluations can help us to understand the vaccine's effect on reducing infection and disease when used in real-world conditions. They can also address important questions that were either not studied or were incompletely studied in the trials and that will inform evolving vaccine policy, including assessment of the duration of effectiveness; effectiveness in key subpopulations, such as the very old or immunocompromised; against severe disease and death due to COVID-19; against emerging SARS-CoV-2 variants of concern; and with different vaccination schedules, such as number of doses and varying dosing intervals. WHO convened an expert panel to develop interim best practice guidance for COVID-19 vaccine effectiveness evaluations. We present a summary of the interim guidance, including discussion of different study designs, priority outcomes to evaluate, potential biases, existing surveillance platforms that can be used, and recommendations for reporting results.


Subject(s)
COVID-19 , Vaccines , COVID-19 Vaccines , Humans , SARS-CoV-2 , World Health Organization
6.
EClinicalMedicine ; 31: 100690, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-964739
8.
Vaccine ; 39(40): 6004-6012, 2021 09 24.
Article in English | MEDLINE | ID: covidwho-915720

ABSTRACT

Given the social and economic upheavals caused by the COVID-19 pandemic, political leaders, health officials, and members of the public are eager for solutions. One of the most promising, if they can be successfully developed, is vaccines. While the technological development of such countermeasures is currently underway, a key social gap remains. Past experience in routine and crisis contexts demonstrates that uptake of vaccines is more complicated than simply making the technology available. Vaccine uptake, and especially the widespread acceptance of vaccines, is a social endeavor that requires consideration of human factors. To provide a starting place for this critical component of a future COVID-19 vaccination campaign in the United States, the 23-person Working Group on Readying Populations for COVID-19 Vaccines was formed. One outcome of this group is a synthesis of the major challenges and opportunities associated with a future COVID-19 vaccination campaign and empirically-informed recommendations to advance public understanding of, access to, and acceptance of vaccines that protect against SARS-CoV-2. While not inclusive of all possible steps than could or should be done to facilitate COVID-19 vaccination, the working group believes that the recommendations provided are essential for a successful vaccination program.


Subject(s)
COVID-19 , Vaccines , COVID-19 Vaccines , Humans , Pandemics/prevention & control , SARS-CoV-2 , United States , Vaccination
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