We fitted incubation period data for each subvariant to the gamma distribution model and calculated parameters and 95% CI within a Bayesian inference framework. 45 C.F.R. Nasal congestion. Congestion or runny nose. The role of antiviral treatment in the COVID-19 pandemic. Uncommon presentations of COVID-19 can occur, might vary by the age of the patient, and are a challenge to recognize. doi:10.1001/jamanetworkopen.2021.11182, Feldstein LR, Tenforde MW, Friedman KG, et al. Clin Infect Dis. For the week ending December 4, the Delta variant accounted for >99.9% of circulating SARS-CoV-2 variants. The omicron variant may create mild COVID-19 symptoms and reinfect previously infected COVID-19 patients, but it could have a shorter incubation time than previous COVID-19 strains, according to a new Centers for Disease Control and Prevention report.. CDC investigates omicron variant spread. Clin Infect Dis. The Centers for Disease Control and Prevention recently shortened its isolation guideline s, citing evidence that COVID is most contagious 1 to 2 days before someone starts feeling symptoms and 2 to 3 days after. "What we've seen with omicron compared to the previous incubation time -- which is seven days between time exposed to . Pediatr Infect Dis J. Dec 1 2021;40(12):e482-e487. Health and Human Services. Accessed December 3, 2021. Characteristics of the cases described in this report might also not be generalizable because case findings might be associated with individual characteristics (e.g., persons with recent international travel might be more likely to be younger and vaccinated). Clinical Presentation and Outcomes of Pregnant Women With Coronavirus Disease 2019: A Systematic Review and Meta-analysis. Effectiveness of two-dose vaccination with mRNA COVID-19 vaccines against COVID-19-associated hospitalizations among immunocompromised adults-Nine States, January-September 2021. Among these cases of COVID-19 attributed to the Omicron variant, 34 (79%) occurred inpersons whocompleted the primary series of an FDA-authorized or approved COVID-19 vaccine 14 days before symptom onset or receipt of a positive SARS-CoV-2 test result, including 14 who had received an additional or booster dose; five of the 14 persons had received the additional dose <14 days before symptom onset. A shorter incubation suggests a shorter quarantine period for BA.5 than for other variants. As of December 8, a total of 22 states had identified at least one Omicron variant case, including some that indicate community transmission. Duration of infectiousness and correlation with RT-PCR cycle threshold values in cases of COVID-19, England, January to May 2020. doi:10.1016/j.cmi.2021.07.030, Abu-Raddad LJ, Chemaitelly H, Bertollini R, National Study Group for C-E. Severity of SARS-CoV-2 Reinfections as Compared with Primary Infections. The mean virus incubation period during the SARS-CoV-2 Omicron BA.5dominant period in Japan was 2.6 (95% CI 2.52.8) days, which was less than during the Delta-dominant period. Aug 1 2021;175(8):837-845. doi:10.1001/jamapediatrics.2021.0630, Miller AD, Zambrano LD, Yousaf AR, et al. Late Conditions Diagnosed 1-4 Months Following an Initial Coronavirus Disease 2019 (COVID-19) Encounter: A Matched-Cohort Study Using Inpatient and Outpatient Administrative Data-United States, 1 March-30 June 2020. Sep 1 2020;370:m3320. For the most recent updates on COVID-19, visit our coronavirus news page. doi:10.1097/inf.0000000000003328, Kompaniyets L, Bull-Otterson L, Boehmer TK, et al. BMC Infect Dis. Effectiveness of a Third Dose of Pfizer-BioNTech and Moderna Vaccines in Preventing COVID-19 Hospitalization Among Immunocompetent and Immunocompromised Adults - United States, August-December 2021. https://www.whitehouse.gov/briefing-room/presidential-actions/2021/11/26/a-proclamation-on-suspension-of-entry-as-immigrants-and-nonimmigrants-of-certain-additional-persons-who-pose-a-risk-of-transmitting-coronavirus-disease-2019external icon, https://www.cdc.gov/quarantine/fr-proof-negative-test.html, *** https://www.cdc.gov/quarantine/order-collect-contact-info.html, https://www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/overview.html, https://www.cdc.gov/coronavirus/2019-ncov/your-health/quarantine-isolation.html, https://www.cdc.gov/quarantine/masks/mask-travel-guidance.html, **** https://www.cdc.gov/coronavirus/2019-ncov/travelers/international-travel/index.html. But while it's taking less time to develop symptoms, for many people it is also taking less time to recover. According to earlier CDC guidance, COVID symptoms can appear anywhere from two to 14 days after someone is exposed to the virus. N Engl J Med. SARS-CoV-2 Incubation Period during the Omicron BA.5-Dominant Period in Japan On This Page The Study. CDC twenty four seven. SARS-CoV-2 shedding dynamics across the respiratory tract, sex, and disease severity for adult and pediatric COVID-19. A study of the Oslo Christmas party outbreak found the incubation period could be about three days, compared with 4.3 days for delta and five days for other variants. Racial Bias in Pulse Oximetry Measurement. Detection of SARS-CoV-2 Among Residents and Staff Members of an Independent and Assisted Living Community for Older Adults - Seattle, Washington, 2020. Chest. According to Japans Infectious Diseases Control Law, public health centers (PHCs) must be notified of all COVID-19 cases and conduct contact tracing (4). *** To date, at least one confirmed case attributed to the Omicron variant has been identified in the United States through these aircraft contact investigation efforts. Accessed December 2, 2021. To accelerate detection of COVID-19 cases attributed to the Omicron variant until they are common enough to be reliably measured by routine genomic surveillance, enhanced surveillance was initiated through National SARS-CoV-2 Strain Surveillance on November 28. Overall, its important to get vaccinated and boosted against COVID-19 to have protection against severe outcomes of the virus. https://covid.cdc.gov/covid-data-tracker/#variant-proportions Top References CDC. Even if most infections are mild, a highly transmissible variant could result in enough cases to overwhelm health systems. These cookies may also be used for advertising purposes by these third parties. For COVID-19, this can reach up to 14 days after virus exposure. Risk Factors for Severe COVID-19 in Children. Implementation of concurrent prevention strategies, including vaccination, masking, increasing ventilation, testing, quarantine, and isolation, are recommended to slow transmission of SARS-CoV-2, including variants such as Omicron, and to protect against severe illness and death from COVID-19. We defined patients in the Delta-dominant period as those who had symptom onset during July 23September 14, 2021, and either they or their contacts were confirmed to have L452R-positive SARS-CoV-2. JAMA Network Open. Incubation period of COVID-19 caused by unique SARS-CoV-2 strains: a systematic review and meta-analysis. All information these cookies collect is aggregated and therefore anonymous. SARS-CoV-2 Infection and Hospitalization Among Adults Aged >/=18 Years, by Vaccination Status, Before and During SARS-CoV-2 B.1.1.529 (Omicron) Variant Predominance - Los Angeles County, California, November 7, 2021-January 8, 2022. . Nov 2022;53:101624. doi:10.1016/j.eclinm.2022.101624, Tenforde MW, Olson SM, Self WH, et al. Jan 2021;21(1):52-58. doi:10.1016/S1473-3099(20)30764-7, Wang J, Kaperak C, Sato T, Sakuraba A. COVID-19 reinfection: a rapid systematic review of case reports and case series. World Health Organization. . The decrease in isolation time was largely to decrease the impact and disruption of infection on day-to-day life and allow people to return to work sooner, Oller said. Among 43 cases with initial follow-up, one hospitalization and no deaths were reported. Post-COVID-19 Symptoms and Conditions Among Children and Adolescents - United States, March 1, 2020-January 31, 2022. You can review and change the way we collect information below. "Omicron has the shortest incubation period. On December 10, 2021, this report was posted online as an MMWR Early Release. Jama. The mean virus incubation period during the SARS-CoV-2 Omicron BA.5-dominant period in Japan was 2.6 (95% CI 2.5-2.8) days, which was less than during the Delta-dominant period. Verywell Health's content is for informational and educational purposes only. COVID-19-Associated Hospitalizations Among Adults During SARS-CoV-2 Delta and Omicron Variant Predominance, by Race/Ethnicity and Vaccination Status - COVID-NET, 14 States, July 2021-January 2022. 2021/08/01/ 2021;46:520-524. doi:https://doi.org/10.1016/j.ajem.2020.11.006, Nasiri N, Sharifi H, Bazrafshan A, Noori A, Karamouzian M, Sharifi A. Ocular Manifestations of COVID-19: A Systematic Review and Meta-analysis. JAMA. Pregnancy and postpartum outcomes in a universally tested population for SARS-CoV-2 in New York City: a prospective cohort study. An update on COVID-19 and pregnancy. With the original COVID-19 variant, symptoms showed up on average around five to six days after contact with an infected person, [while] the Delta variants incubation period was around four days, Beth Oller, MD, a family physician at Solomon Valley Family Medicine, told Verywell. Omicrons incubation period is about two to four days, which is generally shorter than the previous variants. The clinical presentation of COVID-19 ranges from asymptomatic to critical illness. 2021;325(11):1074. doi:10.1001/jama.2021.2091, Wanga V, Gerdes ME, Shi DS, et al. Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis. The CDC says that its guidelines were updated to reflect growing evidence that suggests transmission of COVID-19 often occurs one to two days before the onset of symptoms and during the two to . You will be subject to the destination website's privacy policy when you follow the link. Coronavirus Disease 2019 Case Surveillance - United States, January 22-May 30, 2020. May 19 2022;386(20):1899-1909. doi:10.1056/NEJMoa2202826, Zambrano LD, Ellington S, Strid P, et al. CDC COVID-19 Response Team (View author affiliations). Trends in Geographic and Temporal Distribution of US Children With Multisystem Inflammatory Syndrome During the COVID-19 Pandemic. Finally, increasing patient numbers might have influenced the quality of contact tracing by the PHC. Waltham, MA: ThermoFisher Scientific; 2021. Feb 2022;226(2):177-186. doi:10.1016/j.ajog.2021.08.054, Barbero P, Mugerza L, Herraiz I, et al. Cmaj. Weekly / December 17, 2021 / 70(50);1731-1734. Investigation of a SARS-CoV-2 B.1.1.529 (Omicron) Variant Cluster - Nebraska, November-December 2021. Characterizing long COVID in an international cohort: 7 months of symptoms and their impact. Scientists in South Africa and elsewhere have established systems that allow study of the laboratory, clinical, and epidemiologic characteristics; CDC is collaborating with health officials around the world to learn more about the characteristics of patients with Omicron variant infections. The rapid emergence and worldwide detection of the SARS-CoV-2 Omicron variant underscores the importance of robust genomic surveillance systems and prompt information-sharing among global public health partners. Anyone exhibiting symptoms should get tested for COVID-19. Interim clinical guidance for management of patients with confirmed coronavirus disease (COVID-19), What we know about quarantine and isolation, CDC updates and shortens recommended isolation and quarantine period for general population, High rates of rapid antigen test positivity after 5 days of isolation for COVID-19, Modeling the effect of age on quantiles of the incubation period distribution of COVID-19. Sep 30 2022;75(7):1201-1209. doi:10.1093/cid/ciac072, Zambrano LD, Newhams MM, Olson SM, et al. doi:http://dx.doi.org/10.15585/mmwr.mm7113e1, Pingali C, Meghani M, Razzaghi H, et al. Dermatology. Lancet Reg Health Eur. The CDC released early information on 43 cases attributed to omicron in the U.S. from Dec. 1 to 8, saying 34 of those individuals were fully vaccinated, including 14 who had gotten a booster dose . According to the CDC, the following are symptoms of a COVID infection: Fever or chills Cough Shortness of breath or difficulty breathing Fatigue Muscle or body aches Headache New loss of taste or. BMC Med 2021;19:94. Jan-Mar 2021;16(1):103-112. doi:10.18502/jovr.v16i1.8256, Tan E, Song J, Deane AM, Plummer MP. The earliest date of symptom onset was November 15 in a person with a history of international travel. Dec 2021;27(12):1860 e7-1860 e10. Health experts say incubation times could be changing due to omicron, but those who test early should continue testing even if they get negative results. CDC has developed a working case definition for MIS-A. We enrolled COVID-19 infector/infectee pairs who lived within the Itako PHC jurisdiction and had a single definite close contact date with patients who had COVID-19 without other potential transmission settings. endorsement of these organizations or their programs by CDC or the U.S.
MMWR Morb Mortal Wkly Rep. Sep 10 2021;70(36):1249-1254. doi:10.15585/mmwr.mm7036e1, Cloete J, Kruger A, Masha M, et al. Feb 17 2022;386(7):698-700. doi:10.1056/NEJMc2119236, Leon TM, Dorabawila V, Nelson L, et al. For those without symptoms, CDC guidance states they are considered contagious at least two days before their positive test. Specimens that display SGTFs have a higher likelihood to be Omicron (although SGTFs are not unique to Omicron) based on a mutation (6970 deletion) that reduces S-gene target amplification in some PCR assays. doi:10.1093/ofid/ofab428, Rader B.; Gertz AL, D.; Gilmer, M.; Wronski, L.; Astley, C.; Sewalk, K.; Varrelman, T.; Cohen, J.; Parikh, R.; Reese, H.; Reed, C.; Brownstein J. COVID-19 Incidence and Death Rates Among Unvaccinated and Fully Vaccinated Adults with and Without Booster Doses During Periods of Delta and Omicron Variant Emergence - 25 U.S. Jurisdictions, April 4-December 25, 2021. In summary, our results indicate that the SARS-CoV-2 Omicron BA.5 subvariant has a shorter incubation period than other variants. The 95th percentile distribution for incubation period was estimated at 4.5 (95% CI 4.14.9) days during the BA.5dominant period, 5.2 (95% CI 4.65.9) days during the BA.1dominant period, and 6.1 (95% CI 5.56.8) days during the Delta-dominant period (Table 1; Figure). University of Texas at Austin. The first limitation of our study is that the infector and infectee might have been mutually misclassified, leading to overestimation. (8) Multiple publications have reported cases of people with abnormalities on chest imaging that are consistent with COVID-19 very early in the course of illness, even before the onset of symptoms or a positive COVID-19 test. Jan 18 2022;327(3):281-283. doi:10.1001/jama.2021.23262, Nygaard U, Holm M, Hartling UB, et al. Distinguishing Multisystem Inflammatory Syndrome in Children From COVID-19, Kawasaki Disease and Toxic Shock Syndrome. Nov 2020;2(4):100246. doi:10.1016/j.ajogmf.2020.100246, Galang RR, Newton SM, Woodworth KR, et al. Journal of investigative medicine : the official publication of the American Federation for Clinical Research. . Hospitalizations Associated with COVID-19 Among Children and Adolescents - COVID-NET, 14 States, March 1, 2020-August 14, 2021. and/or the original MMWR paper copy for printable versions of official text, figures, and tables. Read our. Fourteen (33%) persons reported international travel during the 14 days preceding symptom onset or receipt of a positive test result. Preprint posted onlineFebruary 2, 2022. doi:10.1101/2022.02.01.22269931, Liu X, Wang L, Ma X, Wang J, Wu L. Modeling the effect of age on quantiles of the incubation period distribution of COVID-19. according to reports from the CDC. JAMA Netw Open. Virus Evol 2021;7:veab064. Headache. Tables Table 1. The 95th percentile distribution for incubation period among patients during the BA.5dominant period appeared shorter than that during the BA.1dominant period, although the difference was not statistically significant. Early research indicates that the newer versions may be more transmissible and more . Community and close contact exposures associated with COVID-19 among symptomatic adults. Thank you, {{form.email}}, for signing up. Our results might warrant a reduction of the quarantine period from 7 to 5 days during the BA.5dominant period in Japan (13). May 2020;38(5):925-928. doi:10.1016/j.ajem.2019.07.020, Iuliano AD, Brunkard JM, Boehmer TK, et al. CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. An early CDC study, released on Tuesday, examined an Omicron cluster in Nebraska and found that the time between exposure and infection - known as the incubation period - may be around three . Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. Am J Obstet Gynecol. Clin Infect Dis. For Immediate Release: Monday, December 27, 2021 Contact: Media Relations (404) 639-3286 Given what we currently know about COVID-19 and the Omicron variant, CDC is shortening the recommended time for isolation for the public. What is Omicron's incubation period? This is shorter than with Delta and earlier variants. Viral Load The amount of virus that builds up in someone's body is known as. The mean during the BA.1dominant period was 2.9 (95% CI 2.63.2) days, and the median was 2.7 (95% CI 2.53.0) days. SARS-CoV-2 B.1.1.529 (Omicron) Variant United States, December 18, 2021. According to the Australian Department of Health, the incubation period for COVID-19 can range between one and 14 days, with most cases displaying symptoms by day 5 or 6 after exposure. of pages found at these sites. Scientists around the world are working to rapidly learn more about the Omicron variant to better understand how easily it might be transmitted and the effectiveness of current diagnostic tests, vaccines, and therapeutics against this variant. Saving Lives, Protecting People, https://www.cdc.gov/coronavirus/2019-ncov/variants/spheres.html, https://covid.cdc.gov/covid-data-tracker/#variant-proportion, https://www.whitehouse.gov/briefing-room/presidential-actions/2021/11/26/a-proclamation-on-suspension-of-entry-as-immigrants-and-nonimmigrants-of-certain-additional-persons-who-pose-a-risk-of-transmitting-coronavirus-disease-2019, https://www.cdc.gov/quarantine/fr-proof-negative-test.html, https://www.cdc.gov/quarantine/order-collect-contact-info.html, https://www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/overview.html, https://www.cdc.gov/coronavirus/2019-ncov/your-health/quarantine-isolation.html, https://www.cdc.gov/quarantine/masks/mask-travel-guidance.html, https://www.cdc.gov/coronavirus/2019-ncov/travelers/international-travel/index.html, https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/scientific-brief-omicron-variant.html, https://www.who.int/news/item/26-11-2021-classification-of-omicron-(b.1.1.529)-sars-cov-2-variant-of-concern, https://covid-19.tacc.utexas.edu/media/filer_public/d9/d9/d9d99a16-704e-4c00-ab41-069957c6c25e/variant_calculator_user_guide.pdf, https://www.thermofisher.com/us/en/home/clinical/clinical-genomics/pathogen-detection-solutions/covid-19-sars-cov-2/multiplex.html, https://doi.org/10.1186/s12916-021-01975-w, https://www.nicd.ac.za/frequently-asked-questions-for-the-b-1-1-529-mutated-sars-cov-2-lineage-in-south-africa/, Centers for Disease Control and Prevention, U.S. Department of Health & Human Services, Shortness of breath or difficulty breathing. Jan 15 2021;doi:10.1001/jamainternmed.2020.9241, Matar R, Alrahmani L, Monzer N, et al. Sect. Updated Jan. 27, 2023 The omicron subvariant of COVID-19, BA.5, became one of the dominant strains of the virus in the fall of 2022 in the U.S. At that time, it was the most easily spread strain to date and is able to evade immunity from COVID infection and vaccination. Therefore, isolating for five days may not be enough, even if one is asymptomatic, Weiss said. Short-term and Long-term Rates of Postacute Sequelae of SARS-CoV-2 Infection: A Systematic Review. Multisystem inflammatory syndrome in adults (MIS-A): case finding through systematic review of electronic medical records. When Should You Get Tested After a COVID-19 Exposure? The risk of severe COVID-19 increases with increasing age over 40 years and with increasing number of certain, Shortness of breath or difficulty breathing. Omicron and its subvariants have shorter incubation periods, which means it takes less time for symptoms to appear after exposure to the virus. Of secondary cases, 90% had an incubation period of 6 days for Omicron and 7 days for Delta. Johansson MA, Wolford H, Paul P, et al. Landon E, Bartlett AH, Marrs R, Guenette C, Weber SC, Mina MJ. Study: Newer COVID-19 Variants Have Shorter Incubation Periods. Dr. Roy Gulick, the chief of infectious diseases at Weill Cornell Medical Center and NewYork-Presbyterian, said typical symptoms of the omicron subvariants include: Sore throat. Underlying Medical Conditions and Severe Illness Among 540,667 Adults Hospitalized With COVID-19, March 2020-March 2021. Jun 2021;299(3):E262-e279. Furthermore, children usually have mild symptoms, and average viral shedding might be less than that of an adult (15). Ogata T, Tanaka H. SARS-CoV-2 Incubation Period during the Omicron BA.5Dominant Period in Japan. Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Data is collected weekly and does not include downloads and attachments. People with COVID-19 may be asymptomatic or experience one or more of the following symptoms(5): The NIH COVID-19 Treatment Guidelinesgroup SARS-CoV-2 infection into five categories based on severity of illness: Studies have documented infection with SARS-CoV-2 in people who never develop symptoms (asymptomatic presentation) and in people who are asymptomatic when tested but then develop symptoms later (presymptomatic presentation). Table 2. CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. (6,7) However, it is unclear what percentage of people who have asymptomatic infection progress to clinical disease (presymptomatic presentation). COVID-19 in immunocompromised patients: A systematic review of cancer, hematopoietic cell and solid organ transplant patients. In December, the CDC issued new guidance reducing the isolation period of infected individuals to five days, if their symptoms have fully resolved. Timely case investigation and contact tracing can help ensure compliance with isolation and quarantine guidance and link persons with positive SARS-CoV-2 test results and their close contacts to testing and supportive services. MMWR Morb Mortal Wkly Rep. Mar 4 2022;71(9):335-340. doi:10.15585/mmwr.mm7109a2, Burki TK. Multisystem Inflammatory Syndrome in Children During Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Delta and Omicron Variant Circulation-United States, July 2021-January 2022. Genomic evidence for reinfection with SARS-CoV-2: a case study. JAMA Netw Open. High rates of rapid antigen test positivity after 5 days of isolation for COVID-19. Epidemiology of Infections with SARS-CoV-2 Omicron BA.2 Variant, Hong Kong, January-March 2022. While long COVID, hospitalization, or death is less likely if a person is vaccinated, it is still possible and is not a risk that most of us want to take. Dr. Ogata has been engaged in the field of public health for 40 years as a medical officer and is the director of the Itako Public Health Center. Classification of Omicron (B.1.1.529): SARS-CoV-2 variant of concern. MMWR Morb Mortal Wkly Rep. Aug 13 2021;70(32):1081-1083. doi:10.15585/mmwr.mm7032e1, National Center for Immunization and Respiratory Diseases (NCIRD), Post-COVID Conditions: Healthcare Providers, Decontamination & Reuse of N95 Respirators, Purchasing N95 Respirators from Another Country, Powered Air Purifying Respirators (PAPRs), U.S. Department of Health & Human Services. Omicron has numerous mutations with potential to increase transmissibility, confer resistance to therapeutics, or partially escape infection- or vaccine-induced immunity (2). MMWR Morb Mortal Wkly Rep. Sep 10 2021;70(36):1235-1241. doi:10.15585/mmwr.mm7036a1, Bull-Otterson LB, S.; Saydah, S.; Boehmer, T.; Adjei, S.; Gray, S.; Harris, A. PostCOVID Conditions Among Adult COVID-19 Survivors Aged 1864 and 65 Years United States, March 2020November 2021. Jul 15 2021;73(Suppl 1):S5-S16. The incubation period might be influenced by various factors, such as viral load, environmental setting, patient immune response, severity of disease, and selection biases. When we fitted incubation period data from the BA.5dominant period to parametric distribution models, the Akaike information criterion for gamma distribution was smaller than that for Gaussian, lognormal, and Weibull distribution models. According to earlier CDC guidance, COVID symptoms can appear anywhere from two to 14 days after someone is exposed to the virus. Apr 2022;21(4):435-451. doi:10.1080/14760584.2022.2035222, Lee A, Wong SY, Chai LYA, et al. The average duration of illness is shorter with Omicron than Delta: five days compared to six. In part, I think [the incubation period] strongly depends upon the infected human.. * International travel within 14 days of symptom onset or, if asymptomatic, first positive SARS-CoV-2 test result. But in the case of omicron, the incubation period is much shorter- just three days, according to studies by the Centers for Disease Control and Prevention. What are the implications for public health practice? A study released Tuesday by the CDC suggestes that the omicron variant may have a shorter incubation period 72 hours than previous variants of the disease, which typically took four days . Estimating the duration of infectiousness is more challenging than measuring incubation periods; one study that measured viral load of Omicron suggested that viral load had diminished by days 10-13, which is in line with our findings ( 6 ). part 46.102(l)(2); 21 C.F.R. ThermoFisher Scientific. This interagency group focuses on the rapid characterization of emerging variants and actively monitors their potential impact on critical SARS-CoV-2 countermeasures, including vaccines, therapeutics, and diagnostics. OToole , Scher E, Underwood A, et al. MMWR Morb Mortal Wkly Rep. Apr 30 2021;70(17):644-650. doi:10.15585/mmwr.mm7017e3, Chevinsky JR, Tao G, Lavery AM, et al.