Post-vaccination data

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Post-vaccination data

Updated on 14/09/2021

What is a COVID-19 case after vaccination?
Post-vaccination cases are defined as fully vaccinated individuals who became a confirmed or probable case of COVID-19 (i.e., who had a PCR or antigen-positive test for the SARS-CoV-2 virus). ) more than 14 days after completing it in full. COVID-19 vaccination series of one or two doses. They are also known as vaccine advancement cases.

What is a hospitalization for COVID-19 after vaccination?
Post-vaccination hospitalizations are COVID-19-related hospitalizations among people who were admitted with COVID-19 as the primary diagnosis / cause of admission after full vaccination.

What is death from COVID-19 after vaccination?
Post-vaccination deaths are a subset of post-vaccination cases. Specifically, these are COVID-19-related deaths among individuals who became a confirmed or probable case of COVID-19 more than 14 days after completing their full series of COVID-19 vaccinations.

How are COVID-19 cases and deaths identified after vaccination?
The Pennsylvania Department of Health identifies cases using COVID test results reported by laboratories and health care providers. Post-vaccination cases are identified by linking the disease surveillance record (i.e., case data) to the vaccination record to find individuals who have a positive initial COVID-19 test at least 14 days after ‘have completed their full series of vaccinations. Occasionally information on vaccination obtained from providers or patient interviews is used if the case is not on the vaccine registry. To identify COVID-19-related deaths, the department also links case data to the state death registry. Deaths from COVID-19 in people determined as post-vaccination cases are considered post-vaccination deaths.

How are COVID-19 hospitalizations identified after vaccination?
The PA DOH collects hospitalization data both at the patient level and aggregated according to the vaccination status of the hospitals. Currently, the Department of Health Medicine is reporting valid and aggregated hospitalization and vaccination status data, as reported by themselves by hospitals. DOH will continue to work with hospitals to improve the validity and finalization of submitted data.

Why do we track post-vaccination events?
Monitoring of COVID-19 events that occur after vaccination is important to monitor public health. Although COVID-19 vaccines are safe and effective, some cases, hospitalizations, and deaths are still expected in vaccinated individuals, as no vaccine is 100% effective. If the incidence or severity of post-vaccination cases increases, it may be a sign of reduced protection against a variant.

What is the current data on post-vaccination events in Pennsylvania?
The data show that COVID-19 vaccines are highly effective in preventing hospitalizations and deaths, even when more post-vaccination cases occur in the context of more transmissible variants.

Between January 1, 2021 and September 7, 2021 in Pennsylvania, 97% of COVID-19-related deaths were in unvaccinated or not fully vaccinated individuals.

  • Among a total of 6,472 COVID-19-related deaths identified in Pennsylvania in 2021, there were at least 213 post-vaccination deaths identified (3%).
    • The cumulative incidence of death among unvaccinated and not fully vaccinated was 7.9-fold higher than the incidence of mortality among fully vaccinated (56 vs. 7 per 100,000).

Between January 1, 2021 and September 6, 2021 in Pennsylvania, 95% of hospitalizations with COVID-19 as the primary diagnosis / cause of admission reported hospitalizations in unvaccinated or not fully vaccinated individuals.

  • Among a total of 34,468 hospitalizations with COVID-19 as the primary diagnosis / reported cause of admission in Pennsylvania, 1,820 were reported to have occurred in fully vaccinated pensilvans. These figures represent data from 55% of all hospitals and 69% of acute care hospitals in Pennsylvania.

Between January 1, 2021 and September 7, 2021 in Pennsylvania, 94% of reported COVID-19 cases were in unvaccinated or not fully vaccinated individuals.

  • Among a total of 639,729 positive cases, 35,389 post-vaccination cases (6%) have been identified.
    • The cumulative incidence of cases among unvaccinated and not fully vaccinated was 7.1 times higher than the incidence of cases among fully vaccinated (5,840 vs. 819 per 100,000).

Technical notes:

  • Vaccination counts were obtained from the two Pennsylvania vaccine registries: SIIS (which collects information on vaccinations administered in PA outside of Philadelphia) and PhilaVax (Philadelphia Department of Public Health) [PDPH] vaccine register).
    • For SIIS data, we excluded residents of the state and people with unknown addresses; and individuals were not considered fully vaccinated until 14 days after receiving the second of two doses of the Pfizer or Moderna vaccines or one dose of the Janssen vaccine. Please note that this differs from the Department of Health (PADOH) vaccine scorecard, where the 14-day waiting period is not taken into account when calculating the percentage fully covered.
    • PhilaVax data have been obtained from the PDPH website. We included residents and nonresidents in Philadelphia, as most nonresidents probably reside in other PA counties rather than out of state. As a result, some out-of-state residents may be included in vaccination counts. The number of fully vaccinated people listed on the PDPH website also does not take into account the vaccination waiting period of 14 days after termination. We were unable to adjust PhilaVax data for the waiting period; As a result, the percentage actually fully vaccinated may be slightly overestimated in this report. PhilaVax Vaccination Data for Philadelphia was estimated on the PDPH website on cumulative weekly vaccination numbers. To estimate the daily number of PhilaVax vaccines, the difference between the cumulative estimates for each week was calculated and each difference was divided by 7. The estimate of PhilaVax for fully vaccinated individuals does not take into account the waiting period. of 14 days between the last dose of vaccination and date of effectiveness of the vaccines.
  • COVID-19 case numbers were obtained from PADOHand PDPH electronic disease surveillance systems. Advanced vaccine cases were identified by matching vaccine registry data with case data submitted to the disease surveillance system or from information obtained in a case investigation.
    • It was considered that people with the same date of birth and the same name or surnames, or very similar, in the case and vaccine registry were the same person. Significant variations in the name or data entry errors in the name or date of birth can cause some cases of vaccine progress to be lost. Results may change as matching strategies are refined over time.
    • The date of collection of samples from the first PCR or COVID-19 positive antigen test of the case was used as a substitute for the date of infection. Because only one infection per individual is detected in this test and this infection is the first infection, some cases of vaccine progression may be missed in those who have had COVID-19 more than once in 2021.
  • COVID-19-related deaths among COVID cases were identified by matching case data from our disease surveillance system with death record data, using probabilistic matching software.
    • The following deaths from COVID-19 were not included: (1) deaths from the state registry of deaths that did not match the disease surveillance system due to data entry errors or significant variations in names, and (2) deaths in the state death registry that did not have a corresponding positive PCR or antigen test in the disease surveillance system.
    • The state register of deaths determines whether a death is related to the COVID following the criteria developed by the National Center for Health Statistics. Because it takes time for deaths to be reported, classified, and adapted to case data, deaths may be delayed by approximately three weeks.
  • The number of hospitalizations during the previous day with COVID-19 as the primary diagnosis / cause of admission, as well as the vaccination states associated with patients, are self-reported by acute hospitals in the data collection tool. essential elements of information (EEI) in CORVENA every day at 10 am. Daily reports of these data from the previous day began on September 7, 2021. Each acute care hospital was also asked to report the total number of hospitalizations with COVID-19 as the primary diagnosis / cause of admission. , as well as the vaccination states associated with patients. , for the period from January 1, 2021 to September 6, 2021 through a survey distributed by the DOH in September 2021.
    • Only the data that have passed the simple validity checks are included in the final report. Validity checks only ensure that: (1) values ​​were presented for the total number of hospitalizations with COVID-19 as the primary diagnosis / cause of admission and for each vaccination status, (2) that the total number of hospitalizations with COVID-19 as the primary diagnosis / cause of admission was not greater than the total number of patients confirmed to have COVID-19 and (3) that the sum of patients hospitalized by vaccination status equaled the number total hospitalizations with COVID-19 the main diagnosis / cause of admission.
    • NEDSS patient-level case and hospitalization data are not currently used for the hospitalization figures in this report. As such, when the vaccination status of a hospitalized patient is unknown, they are included if they are not fully vaccinated.
  • The incidence of cases among the fully vaccinated population is expected to increase as vaccinated people are more likely to be exposed to infectious people, especially people infected with more transmissible variants. Case count, population percentages, and incidence calculations include all ages of BP, both adults and children.
    • Incidence rates were calculated as follows. The daily incidence rate of cases and deaths was calculated based on the COVID-19 infection count of the day divided by the cumulative number of fully vaccinated (or not fully vaccinated) residents of the previous day. Thus, only people who were completely vaccinated were included in the denominator.
    • To obtain the cumulative incidence rate per 100,000 population, the sum of the daily incidence rates during the period (last 30 days, or days since January 1, 2021) was taken and multiplied by 100,000.

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