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CDC COVID-19 Science Update Database

CDC COVID-19 Science Update Last data update: Dec 14, 2021 . (Total: 2249 Publications)

COVID-19 trends and severity among symptomatic children aged 0-17 years in ten EU countries, 3 August 2020 3 October 2021
Bundle, Nick et al.medRxiv 10.1101/2021.11.25.21266875
type type type type type
Key findings:
  • Pediatric cases and hospitalization rates increased as rates in adult age groups rose (Figure), but severe outcomes were rare.
  • Among symptomatic children, 1.2% (n = 9,611) were hospitalized, 0.08% (n = 640) required intensive care, and 0.01% (n = 84) died.
  • The risk of hospitalization was highest among children aged <1 year (13.1%) and lowest among those aged 813 years (0.6%).
  • Most hospitalized children (83.7%) had no reported comorbidities; however, risks of hospitalization (adjusted odds ratio [aOR]29), intensive care (aOR 8.74), and death (aOR 26.85) were higher among children with any comorbidity compared with no comorbidities.
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Comparative Effectiveness of BNT162b2 and mRNA-1273 Vaccines in U.S. Veterans
Dickerman, Barbra A. et al. N Engl J Med 2021 10.1056/NEJMoa2115463
type type type type

Summary: In matched cohorts of BNT162b2 or mRNA-1273 vaccinated U.S. veterans (n = 219,842 per group) during JanuaryJuly 2021, risk of COVID-19 hospitalization in the 24 weeks after vaccine dose 1 was low in both groups (1.33 events/1,000 persons [95% CI 1.16-1.57] and 0.78 events/1,000 persons [95% CI 0.64-0.91], respectively). However, compared with mRNA-1273, BNT162b2 vaccination was associated with a higher risk of hospitalization (RR 1.70, 95% CI 1.42-2.24) and ICU admission (RR 1.38, 95% CI 1.01-2.42).

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Investigating SARS-CoV-2 breakthrough infections per variant and vaccine type
Dingemans, Jozef et al.medRxiv 10.1101/2021.11.22.21266676
type type type type type

Summary: Among fully vaccinated adults in the Netherlands during JanuaryJuly 2021, SARS-CoV-2 breakthrough infections (n = 378) were most common among individuals vaccinated with ChAdOx1 (0.89%) followed by Ad26.COV2.S (0.46%) and mRNA vaccines (0.14%). Ct values were significantly lower (suggesting higher levels of viral RNA detected) (p<0.01) for breakthrough infections caused by the Delta variant (Ct value = 17) compared with Alpha variant (Ct value = 22). There was no association between SARS-CoV-2 genotype or vaccine type and disease severity.

Visit Weekly CDC COVID-19 Science Update site for the full summary.

Probable Transmission of SARS-CoV-2 Omicron Variant in Quarantine Hotel, Hong Kong, China, November 2021.
Gu Haogao, et al. Emerging infectious diseases 2021 0 0. (2)
type type type type

Summary: The SARS-CoV-2 Omicron variant was detected in an asymptomatic, fully vaccinated traveler staying in a quarantine hotel in Hong Kong. Four days later, Omicron was detected in a 2nd fully vaccinated traveler, who had arrived from a different country on a different day and had stayed in a room across the corridor from the index patient. Viral genomes from these 2 cases differed only by 1 nucleotide. Retrospective investigation, including closed-circuit television camera footage, confirmed that neither case-patient left their room during the quarantine period.

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Effectiveness and durability of protection against future SARS-CoV-2 infection conferred by COVID-19 vaccination and previous infection; findings from the UK SIREN prospective cohort study of healthcare workers March 2020 to September 2021
Hall, Victoria et al.medRxiv 10.1101/2021.11.29.21267006
type type type type type

Summary: Among 35,768 UK healthcare workers (December 2020September 2021), adjusted vaccine effectiveness (aVE) among those who received 2 doses of BNT162b2 up to 6 weeks apart decreased from 85% (95% CI 71%-92%) 1473 days following dose 2 to 58% (95% CI 40%-71%) >193 days after dose 2. Among those with prior infection, infection alone was associated with waning immunity over time. Prior infection plus 2 doses of BNT162b2 was associated with >90% protection from re-infection for at least 15 months after infection.

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Assessment of 4 Doses of SARS-CoV-2 Messenger RNA-Based Vaccine in Recipients of a Solid Organ Transplant.
Kamar Nassim, et al. JAMA network open 2021 0 0. (11) e2136030
type type type

Summary: Among 37 solid organ transplant recipients in France, including 5 who had a weak response and 31 who had no response to the 1st 3 doses of BNT162b2 vaccine, a 4th dose was associated with continued suboptimal immune response. No adverse events were associated with the 4th

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Omicron SARS-CoV-2 variant: a new chapter in the COVID-19 pandemic.
Karim Salim S Abdool, et al. Lancet (London, England) 2021 0 0. (10317) 2126-2128
type type type type type

Summary: In a commentary that reported data from the Department of Health, Government of South Africaexternal icon, COVID-19 cases in South Africa increased from a mean of 280 cases/day during the week before the detection of the Omicron variant to a mean of 800 cases/day the following week. In Gauteng province, data currently indicate that the number of cases doubled faster than was observed during the same phase of the previous 3 waves.

Visit Weekly CDC COVID-19 Science Update site for the full summary.

Viral Dynamics of SARS-CoV-2 Variants in Vaccinated and Unvaccinated Persons
Kissler, Stephen M. et al. N Engl J Med 2021 10.1056/NEJMc2102507
type type type type type

Key findings:
  • Among participants with SARS-CoV-2 infection, levels of viral RNA detected, proliferation duration, clearance duration, and duration of acute infection were similar among those infected with Alpha (B.1.1.7), Delta (B.1.617.2), and other variants not of current interest or concern (Non-VOI/VOC) (Figure).
  • The proportion of participants with a peak Ct <15 (where lower peak Ct indicates higher levels of viral RNA detected) was slightly higher among those with Delta variant infections (13.0%) compared with Alpha variant (6.9%) or Non-VOI/VOC (10.2%) infections.
  • Mean peak levels of viral RNA detected were similar between vaccinated and unvaccinated participants, but breakthrough infections in vaccinated persons cleared faster (mean 5.5 days, 95% credible interval 4.6-6.5) compared with unvaccinated persons (mean 7.5 days, 95% credible interval 6.8-8.2).
Visit Weekly CDC COVID-19 Science Update site for the full summary.

Third COVID-19 Vaccine Dose Boosts Neutralising Antibodies in Poor Responders
Lake, Douglas F. et al.medRxiv 10.1101/2021.11.30.21266716
type type type type

Key findings:
  • 24 weeks after a 2nd dose of mRNA COVID vaccine, 25% of adults had SARS-CoV-2 neutralizing antibody (NAb) capacity <50% to receptor binding domain (RBD) and were considered vaccine poor responders (VPRs) (Figure).
  • 14% of 2-dose mRNA-1273 (Moderna) recipients were VPRs, compared with 31% of 2-dose BNT162b2 (Comirnaty, Pfizer/BioNTech) recipients.
  • VPRs who received a 3rd vaccine dose showed an average 20-fold increase in NAb capacity (to average neutralization of 88%, range 49%-99%) 24 weeks post-3rd
Visit Weekly CDC COVID-19 Science Update site for the full summary.

Increased risk of SARS-CoV-2 reinfection associated with emergence of the Omicron variant in South Africa
Pulliam, Juliet R. C. et al.medRxiv 10.1101/2021.11.11.21266068
type type type type type type

Summary: Compared with the 1st SARS-CoV-2 wave, the estimated ratio of reinfection hazard to primary infection hazard was lower during wave 2 (Beta [1.351]) (hazard ratio [HR] 0.75, 95% CI 0.59-0.97) and wave 3 (Delta [B.167.2]) (HR 0.71, 95% CI 0.56-0.92), but higher during November 127, 2021 (HR 2.39, 95% CI 1.88-3.11), coincident with the emergence of the Omicron (B.1.1.529) variant (Figure).

Visit Weekly CDC COVID-19 Science Update site for the full summary.

Covid-19 Vaccine Effectiveness in New York State
Rosenberg, Eli S. et al.N Engl J Med 10.1056/NEJMoa2116063
type type type type type type

Key findings:
  • Vaccine effectiveness (VE) against SARS-CoV-2 infection declined from 93.4% in May to 74.2% by the end of August 2021.
  • VE against hospitalization generally remained high for adults of all ages (Figure):
  • Among adults aged 1864 years, VE against hospitalization exceeded 86%.
  • Among adults aged >65 years, VE against hospitalization was higher for recipients of BNT162b2 (Comirnaty, Pfizer/BioNTech) and mRNA-1273 (Moderna) compared with COV2.S (Johnson & Johnson/Janssen) but declined over time; VE among recipients of Ad26.COV2.S did not decline over time.
Visit Weekly CDC COVID-19 Science Update site for the full summary.

Transmission potential of vaccinated and unvaccinated persons infected with the SARS-CoV-2 Delta variant in a federal prison, JulyAugust 2021
Salvatore, Phillip P. et al.medRxiv 10.1101/2021.11.12.21265796
type type type type type

Key findings:
  • During a SARS-CoV-2 Delta (B.1.617.2) variant outbreak in a federal prison, duration of PCR positivity (median 13 days) and viral culture positivity (median 5 days) were similar for fully vaccinated and unvaccinated persons (Figure).
  • Ct values in SARS-CoV-2 positive RT-PCR specimens increased with the number of days since onset, but no significant differences were observed among Ct values when stratified by vaccination status, vaccine product, time since vaccination, or history of prior SARS-CoV-2 infection.
Visit Weekly CDC COVID-19 Science Update site for the full summary.

Risk of COVID-19 hospital admission among children aged 5-17 years with asthma in Scotland: a national incident cohort study.
Shi Ting, et al. The Lancet. Respiratory medicine 2021 0 0.
type type type

Key findings:
  • Children with asthma had a higher risk of COVID-19 hospitalization compared with children without asthma (adjusted hazard ratio [aHR] 1.49, 95% CI 1.14-1.94).
  • Children with poorly controlled asthma (aHR 6.40, 95% CI 3.27-12.53) and those with well-controlled asthma (aHR 1.36, 95% CI 1.02-1.80) had a greater risk of COVID-19 hospitalization compared with children with no asthma (Figure).
  • A history of 2 or more corticosteroid prescriptions (another marker of asthma severity) was also associated with an elevated risk of COVID hospitalization compared with those with no asthma.
Visit Weekly CDC COVID-19 Science Update site for the full summary.

COVID-19 Vaccination Rates and Attitudes Among Young Adults With Recent Experiences of Homelessness
Tucker, Joan S. et al. J Adolesc Health 2021 10.1016/j.jadohealth.2021.11.017
type type type

Summary: In a MarchOctober 2021 survey of 134 young adults (ages 1825 years; 68% male, 87% non-White) who recently experienced homelessness in Los Angeles County, 29% reported they were vaccinated. Among those not vaccinated, 57% strongly disagreed that they would get vaccinated if it was immediately available to them, and 45% strongly agreed that they would not trust the COVID-19 vaccine. Never being offered the vaccine was widely reported among unvaccinated participants (42%), suggesting insufficient outreach to young people experiencing homelessness.

Visit Weekly CDC COVID-19 Science Update site for the full summary.

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This database is an online, continuously updated, searchable database of articles summarized in the CDC COVID-19 Science Update from the CDC COVID-19 Chief Medical Officer and the CDC Office of Library Science. This weekly series provides timely summaries of new COVID-19 publications and preprints on public health priority topics, including vaccines; variants; natural history, reinfection, and health impact; prevention strategies and non-pharmaceutical interventions; testing; transmission risk and dynamics; and health equity.

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COVID-19 Science Update Editions

Content Statistics

Publication Categories:(Priority Areas)
Transmission 1702
Vaccines 1243
Variants 574
Testing 553
Prevention Strategies 291
Health Equity 203
Natural History 112

Publication Types:

Peer-Reviewed 1891
medRxiv 250
Other 43
SSRN 28
bioRxiv 28
Preprints 3
arXiv 2
Res Sq 2
Research Square 1
Global Health Network Preprints 1

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Disclaimer: The purpose of the CDC COVID-19 Science Update is to share public health articles with public health agencies and departments for informational and educational purposes. Materials listed in this Science Update are selected to provide awareness of relevant public health literature. A material’s inclusion and the material itself provided here in full or in part, does not necessarily represent the views of the U.S. Department of Health and Human Services or the CDC, nor does it necessarily imply endorsement of methods or findings. While much of the COVID-19 literature is open access or otherwise freely available, it is the responsibility of the third-party user to determine whether any intellectual property rights govern the use of materials in this Science Update prior to use or distribution. Findings are based on research available at the time of this publication and may be subject to change.

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