Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
To maximize protection from the Delta variant and prevent possibly spreading it to others, get vaccinated as soon as you can and wear a mask indoors in public if you are in an area of substantial or high transmission.
UPDATE
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
UPDATE
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
UPDATE
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

COVID-19 Vaccine Breakthrough Case Investigation and Reporting

COVID-19 Vaccine Breakthrough Case Investigation and Reporting
Updated Oct. 28, 2021

For local health departments, healthcare providers, and clinical laboratories

  • CDC encourages local health departments, healthcare providers, and clinical laboratories that identify a COVID-19 vaccine breakthrough case to:
    • Request the respiratory specimen be held for further testing.
    • Report the case to the state health department where the individual resides for further investigation and reporting to the national system.
  • COVID-19 vaccine breakthrough cases that result in hospitalization or death should be reported to the Vaccine Adverse Event Reporting System (VAERS)external icon.

For state health departments

  • If a possible vaccine breakthrough case is identified:
    • Request that the clinical or public health laboratory hold any residual respiratory specimens from the positive SARS-CoV-2 test.
    • Report the available case data to NNDSS, per normal procedures.
    • Review CDC’s screening questions to assess whether the case meets the COVID-19 vaccine breakthrough investigation criteria.
  • If the reported case meets those criteria, CDC encourages state health departments to:
    • Follow the steps for initiating a COVID-19 vaccine breakthrough case investigation.
    • Record the case in the COVID-19 vaccine breakthrough REDCap database.
  • Because CDC would like to characterize the SARS-CoV-2 lineages responsible for COVID-19 vaccine breakthrough cases, including variants, CDC requests state health departments to:
    • Report sequence results from a state public health laboratory, commercial reference laboratory, or academic laboratory by entering the PANGO lineage and GenBank or GISAID accession number into the COVID-19 vaccine breakthrough REDCap database.
    • If SARS-CoV-2 sequencing will not be performed locally and an acceptable clinical respiratory specimen is available, provide instructions for the testing laboratory to send the residual respiratory specimen to CDC.
    • For cases with a known RT-PCR cycle threshold (Ct) value, submit only specimens with Ct value ≤28 to CDC for sequencing. (Sequencing is not feasible with higher Ct values.)
    • If the Ct value is not known (e.g., positive by antigen test only or by a molecular test that does not provide a Ct value), submit the positive specimen may still be submitted to CDC for RT-PCR and possible sequencing.

How to send CDC sequence data or respiratory specimens from suspected vaccine breakthrough cases

  • CDC would like to receive sequence data and respiratory specimens from COVID-19 vaccine breakthrough cases to assess the SARS-CoV-2 lineage, including variants. When a vaccine breakthrough case is identified, the health department will contact the laboratory to request that any residual respiratory specimen from the positive test be held for sequencing at CDC.
  • The health department also will request the specimen ID numbers and the Ct value for positive RT-PCR results.
  • If SARS-CoV-2 sequencing will not be performed locally and a specimen is available, the state public health laboratory should request the residual clinical respiratory specimen for subsequent shipping to CDC.
    • For cases with a known RT-PCR cycle threshold (Ct) value, submit only specimens with Ct value ≤28 to CDC for sequencing.
    • If the Ct value is not known (e.g., positive by antigen test only or by a molecular test that does not provide a Ct value), the positive specimen may still be submitted to CDC for RT-PCR and potential sequencing.
  • If your laboratory identifies a COVID-19 vaccine breakthrough case, please report it to your state health department so it can initiate the investigation with CDC.
  • These instructions can also be found here: NS3 Submission Guidance Documentsexternal icon.