Note: This dataset is no longer being updated due to the end of the COVID-19 Public Health Emergency.

The California Department of Public Health (CDPH) is identifying vaccination status of COVID-19 cases, hospitalizations, and deaths by analyzing the state immunization registry and registry of confirmed COVID-19 cases. Post-vaccination cases are individuals who have a positive SARS-Cov-2 molecular test (e.g. PCR) at least 14 days after they have completed their primary vaccination series.

Tracking cases of COVID-19 that occur after vaccination is important for monitoring the impact of immunization campaigns. While COVID-19 vaccines are safe and effective, some cases are still expected in persons who have been vaccinated, as no vaccine is 100% effective. For more information, please see https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/COVID-19/Post-Vaccine-COVID19-Cases.aspx

Post-vaccination infection data is updated monthly and includes data on cases, hospitalizations, and deaths among the unvaccinated and the vaccinated. Partially vaccinated individuals are excluded. To account for reporting and processing delays, there is at least a one-month lag in provided data (for example data published on 9/9/22 will include data through 7/31/22).

Notes:

• On September 9, 2022, the post-vaccination data has been changed to compare unvaccinated with those with at least a primary series completed for persons age 5+. These data will be updated monthly (first Thursday of the month) and include at least a one month lag.

• On February 2, 2022, the post-vaccination data has been changed to distinguish between vaccination with a primary series only versus vaccinated and boosted. The previous dataset has been uploaded as an archived table. Additionally, the lag on this data has been extended to 14 days.

• On November 29, 2021, the denominator for calculating vaccine coverage has been changed from age 16+ to age 12+ to reflect new vaccine eligibility criteria. The previous dataset based on age 16+ denominators has been uploaded as an archived table.

As of February 2022, mRNA-based vaccine Comirnaty, developed by Pfizer/Biontech, was the leading COVID-19 vaccine by efficacy rate, showing around 95 percent of efficacy against COVID-19. This statistic illustrates the comparison of select COVID-19 vaccines worldwide, by efficacy.

The annual pre-kindergarten (pre-K) through 12th grade school immunization survey collects school-level, grade-specific data on vaccine coverage and exemptions. The survey collects vaccination and exemption status data on children who entered the school system on or before a specified date during the fall semester. Individual vaccine information on each student is not collected. This table shows the statewide vaccination exemptions (medical and religious) and percentage vaccinated and compliant for each school-entry mandated vaccine series reported by school year, grade, and school type. Percentage of students vaccinated is the number of students with the required number of doses of a given vaccine divided by the total number of students. Data for each grade includes all schools who reported with that given grade level. School-mandated vaccine series for students enrolled in kindergarten are inactivated polio, DTaP (diphtheria, tetanus, and acellular pertussis), MMR (measles, mumps, and rubella), hepatitis B, varicella and hepatitis A. Additional mandated vaccines for students enrolled in 7th grade include meningococcal conjugate vaccine (MCV) and Tdap (tetanus, diphtheria, and acellular pertussis). Influenza vaccine is a requirement for pre-K students only, who are 24 through 59 months of age. Each child has 1 of 4 possible vaccination statutes: Vaccinated, Exempt (Religious), Exempt (Medical) or Non-compliant. The criteria shown below are used to assess whether a child is considered vaccinated. • Flu = at least 1 dose of annual influenza vaccine (pre-K only). This is a school entry requirement only for pre-K students 24 through 59 months of age. • Polio = at least 3 doses of inactivated polio vaccine, with the last dose on or after their 4th birthday. This is a school entry requirement starting in kindergarten. • DTaP = at least 4 doses of DTaP vaccine, with the last dose on or after their 4th birthday. This is a school entry requirement starting in kindergarten. • MMR = at least 2 doses of MMR vaccine separated by at least 28 days, with the 1st dose on or after their 1st birthday. This is a school entry requirement starting in kindergarten. • HepB = at least 3 doses of hepatitis B vaccine, with the last dose on or after 24 weeks of age. This is a school entry requirement starting in kindergarten. • Varicella = at least 2 doses of varicella vaccine separated by at least 28 days, with the 1st dose on or after their 1st birthday, or a reliable history of chickenpox disease. This is a school entry requirement starting in kindergarten. • HepA = at least 2 doses of hepatitis A vaccine, given a minimum of six calendar months apart, with the 1st dose on or after their 1st birthday. This is a school entry requirement starting in kindergarten. Starting with the 2019-2020 school year the annual survey included data collection on hepatitis A vaccine for 7th grade students. • MCV = at least 1 dose of meningococcal conjugate vaccine. This is a school entry requirement starting in 7th grade. • Tdap = at least 1 dose of Tdap vaccine. This is a school entry requirement starting in 7th grade. • All = Percentage of students with all above vaccine series required for that grade level. Children without a record of vaccination, but with serologic proof of immunity to certain diseases (measles, mumps, rubella, hepatitis B, hepatitis A, and varicella), meet school entry requirements and may be counted as vaccinated. Data Limitations and Considerations: • The school level data shown here are as tabulated and reported by schools and discrepancies may exist. • The Immunization Program identifies outliers and internally inconsistent data points and works with schools to resolve any data quality issues, when possible. • CT DPH cannot verify the accuracy of vaccine data for individual children or whether the documentation necessary to claim an exemption has been submitted. • Data are collected at the beginning of the school year, by which time vac

BackgroundRotavirus infection, the most common cause of infant infectious diarrhoea and related deaths worldwide, has imposed a high disease burden in China, especially in Zhejiang Province. This study described the overall epidemiological characteristics and trends of reported rotavirus infections in Zhejiang Province from 2005 to 2022 and evaluated the effectiveness of rotavirus vaccines on the incidence of rotavirus infection.Materials and methodsData on reported cases of rotavirus infection from 2005 to 2022 were extracted from the China Disease Prevention and Control Information System. Information on rotavirus vaccination was obtained from the Zhejiang Provincial Viral Diarrhoea Surveillance Site in 2022. Join-point regression, spatial and temporal aggregation analysis, and an age-period-cohort model were used to explore the epidemiological trends of rotavirus infection. Interrupted time series analysis and an overdispersed Poisson model were used to quantify the effectiveness of rotavirus vaccines.ResultsThe average age-standardized reporting incidence rate (ASRIR) of rotavirus infection in Zhejiang Province was 38.58/100,000, particularly in children aged 0–2 years, who had the highest average annual incidence of 951.63/100,000. The annual ASRIR of all ages showed a significant upward trend before 2017 (average percentage change [APC] = 21.64%) and then decreased significantly (APC = −23.02%). However, in children aged 6–19 years, the annual incidence presented a sustained and significant upward trend over time. The rotavirus infection peak showed a seasonal drift in Zhejiang Province, shifting from November before 2014 to January after 2014. Spatiotemporal aggregation revealed two clusters. The spatio-temporal scanning found two spatio-temporal aggregation areas, the first level spatio-temporal aggregation area was distributed in Hangzhou, Jiaxing and Huzhou, and the second level spatio-temporal aggregation area was Lishui. The age-period-cohort model indicated that the risk of rotavirus infection was primarily concentrated in children aged 0–4 years. The vaccine effectiveness (VE) of rotavirus vaccines was 71.62% (95% confidence interval [CI]: 45.21–86.05%) in children aged 2–59 months, in which the VE of the human-bovine reassortant pentavalent vaccine (RV5) was 91.31% (95% CI: 74.39–97.97%). Since the implementation of RV5 vaccination in September 2018, the number of cases of rotavirus infection per month has decreased by 3,061 (65.27%) in Zhejiang Province.ConclusionThe disease burden of rotavirus infection in Zhejiang Province was high, especially in children. Rotavirus vaccination have significantly reduced the incidence rate of rotavirus infection. Therefore, the prevention of infectious diarrhoea should be further strengthened, especially through increased coverage with the rotavirus vaccine.

NOTE: As of 2/16/2023, this table is not being updated. For data on COVID-19 updated (bivalent) booster coverage by town please to go to https://data.ct.gov/Health-and-Human-Services/COVID-19-Updated-Bivalent-Booster-Coverage-By-Town/bqd5-4jgh.

This table shows the number and percent of residents of each CT town that have initiated COVID-19 vaccination, are fully vaccinated and who have received additional dose 1 by age group.

All data in this report are preliminary; data for previous dates will be updated as new reports are received and data errors are corrected.

In the data shown here, a person who has received at least one dose of COVID-19 vaccine is considered to have initiated vaccination. A person is considered fully vaccinated if he/she has completed a primary vaccination series by receiving 2 doses of the Pfizer, Novavax or Moderna vaccines or 1 dose of the Johnson & Johnson vaccine. The fully vaccinated are a subset of the people who have received at least one dose.

A person who completed a Pfizer, Moderna, Novavax or Johnson & Johnson primary series (as defined above) and then had an additional monovalent dose of COVID-19 vaccine is considered to have had additional dose 1. The additional dose may be Pfizer, Moderna, Novavax or Johnson & Johnson and may be a different type from the primary series. For people who had a primary Pfizer or Moderna series, additional dose 1 was counted starting August 18th, 2021. For people with a Johnson & Johnson primary series additional dose 1 was counted starting October 22nd, 2021. For most people, additional dose 1 is a booster. However, additional dose 1 may represent a supplement to the primary series for a people who is moderately or severely immunosuppressed. Bivalent booster administrations are not included in the additional dose 1 calculations.

The percent with at least one dose many be over-estimated, and the percent fully vaccinated and with additional dose 1 may be under-estimated because of vaccine administration records for individuals that cannot be linked because of differences in how names or date of birth are reported.

Town of residence is verified by geocoding the reported address and then mapping it a town using municipal boundaries. If an address cannot be geocoded, the reported town is used. Out-of-state residents vaccinated by CT providers are excluded from the table.

The population denominators for these town- and age-specific coverage estimates are based on 2014 census estimates. This is the most recent year for which reliable town- and age-specific estimates are available. (https://portal.ct.gov/DPH/Health-Information-Systems--Reporting/Population/Town-Population-with-Demographics). This census data is grouped in 5-year age bands. For vaccine coverage age groupings not consistent with a standard 5-year age band, each age was assumed to be 20% of the total within a 5-year age band. However, given the large deviation from this assumption for Mansfield because of the presence of the University of Connecticut, the age distribution observed in the 2010 census for the age bands 15 to 19 and 20 to 24 was used to estimate the population denominators.

Town-level coverage estimates have been capped at 100%. Observed coverage may be greater than 100% for multiple reasons, including census denominator data not including all individuals that currently reside in the town (e.g., part time residents, change in population size since the census), errors in address data or other reporting errors.

Caution should be used when interpreting coverage estimates for towns with large college/university populations since coverage may be underestimated. In the census, college/university students who live on or just off campus would be counted in the college/university town. However, if a student was vaccinated while studying remotely in his/her hometown, the student may be counted as a vaccine recipient in that town.

Connecticut COVID-19 Vaccine Program providers are required to report information on all COVID-19 vaccine doses administered to CT WiZ, the Connecticut Immunization Information System. Data on doses administered to CT residents out-of-state are being added to CT WiZ jurisdiction-by-jurisdiction. Doses administered by some Federal entities (including Department of Defense, Department of Correction, Department of Veteran’s Affairs, Indian Health Service) are not yet reported to CT WiZ.  Data reported here reflect the vaccination records currently reported to CT WiZ.

SVI refers to the CDC's Social Vulnerability Index - a measure that combines 15 demographic variables to identify communities most vulnerable to negative health impacts from disasters and public health crises. Measures of social vulnerability include socioeconomic status, household composition, disability, race, ethnicity, language, and transportation limitations - among others. Towns with a "yes" in the "Has SVI tract >0.75" field are those that have at least one census tract that is in the top quartile of vulnerability (e.g., a high-need area). 34 towns in Connecticut have at least one census tract in the top quartile for vulnerability.

Note: This dataset takes the place of the original "COVID-19 Vaccinations by Town" dataset (https://data.ct.gov/Health-and-Human-Services/COVID-19-Vaccinations-by-Town/pdqi-ds7f), which will not be updated after 4/15/2021. A dataset of vaccinations by town for all age groups is available here: https://data.ct.gov/Health-and-Human-Services/COVID-19-Vaccinations-by-Town/x7by-h8k4.

As part of continuous data quality improvement efforts, duplicate records were removed from the COVID-19 vaccination data during the weeks of 4/19/2021 and 4/26/2021.

File includes Tables S1-S4. Table S1. General information of the five provinces/municipalities. This table provides general information, including areas, overall population, GDP per capita and population aged 6 months to 14 years, of the five provinces (the four studied province Shandong, Henan, Hunan, Sichuan and the compared municipality Beijing). Table S2. Epidemiologic inputs by province, season, and age group. This table showed the epidemiologic inputs that were used to calculate case numbers by province, season and age group from season 05/06 to 10/11, excluding 09/10 the pandemic season. Table S3. Current situation: influenza vaccination coverage rates among target populations by province, season and age group, influenza vaccine effectiveness by season for all ages. This table used data of vaccination coverage rate and effectiveness of influenza vaccine by province from season 05/06 to 11/12, excluding 09/10 the pandemic season. Table S4. Number of influenza cases and cases averted by vaccination program. It showed the calculation results of number of cases and cases averted by the vaccination program, comparing with no vaccination, from season 05/06 to 10/11, excluding 09/10 the pandemic season. Table S5. Current situation: Cost effectiveness of influenza vaccination program in season 05/06-10/11, 09/10 not included; by province, season and age group. Demonstration of results on cost- effectiveness of comparing the current pay-out-of-pocket policy with no vaccination. Table S6. A: cost-effectiveness of OPTION 1-reminder, by province and age group. Demonstration of results on cost-effectiveness of comparing the current situation with two OPTIONS: OPTION 1 reminder and OPTION 2- sending free influenza vaccination voucher and expanding vaccination sites. (DOCX)

This dataset reports the daily reported number of the 7-day moving average rates of Deaths involving COVID-19 by vaccination status and by age group. Learn how the Government of Ontario is helping to keep Ontarians safe during the 2019 Novel Coronavirus outbreak. Effective November 14, 2024 this page will no longer be updated. Information about COVID-19 and other respiratory viruses is available on Public Health Ontario’s interactive respiratory virus tool: https://www.publichealthontario.ca/en/Data-and-Analysis/Infectious-Disease/Respiratory-Virus-Tool Data includes: * Date on which the death occurred * Age group * 7-day moving average of the last seven days of the death rate per 100,000 for those not fully vaccinated * 7-day moving average of the last seven days of the death rate per 100,000 for those fully vaccinated * 7-day moving average of the last seven days of the death rate per 100,000 for those vaccinated with at least one booster ##Additional notes As of June 16, all COVID-19 datasets will be updated weekly on Thursdays by 2pm. As of January 12, 2024, data from the date of January 1, 2024 onwards reflect updated population estimates. This update specifically impacts data for the 'not fully vaccinated' category. On November 30, 2023 the count of COVID-19 deaths was updated to include missing historical deaths from January 15, 2020 to March 31, 2023. CCM is a dynamic disease reporting system which allows ongoing update to data previously entered. As a result, data extracted from CCM represents a snapshot at the time of extraction and may differ from previous or subsequent results. Public Health Units continually clean up COVID-19 data, correcting for missing or overcounted cases and deaths. These corrections can result in data spikes and current totals being different from previously reported cases and deaths. Observed trends over time should be interpreted with caution for the most recent period due to reporting and/or data entry lags. The data does not include vaccination data for people who did not provide consent for vaccination records to be entered into the provincial COVaxON system. This includes individual records as well as records from some Indigenous communities where those communities have not consented to including vaccination information in COVaxON. “Not fully vaccinated” category includes people with no vaccine and one dose of double-dose vaccine. “People with one dose of double-dose vaccine” category has a small and constantly changing number. The combination will stabilize the results. Spikes, negative numbers and other data anomalies: Due to ongoing data entry and data quality assurance activities in Case and Contact Management system (CCM) file, Public Health Units continually clean up COVID-19, correcting for missing or overcounted cases and deaths. These corrections can result in data spikes, negative numbers and current totals being different from previously reported case and death counts. Public Health Units report cause of death in the CCM based on information available to them at the time of reporting and in accordance with definitions provided by Public Health Ontario. The medical certificate of death is the official record and the cause of death could be different. Deaths are defined per the outcome field in CCM marked as “Fatal”. Deaths in COVID-19 cases identified as unrelated to COVID-19 are not included in the Deaths involving COVID-19 reported. Rates for the most recent days are subject to reporting lags All data reflects totals from 8 p.m. the previous day. This dataset is subject to change.

The California Department of Public Health (CDPH) is identifying vaccination status of COVID-19 cases, hospitalizations, and deaths by analyzing the state immunization registry and registry of confirmed COVID-19 cases. Post-vaccination cases are individuals who have a positive SARS-Cov-2 molecular test (e.g. PCR) at least 14 days after they have completed their primary vaccination series or 14 days after they have completed their booster or additional dose.

Tracking cases of COVID-19 that occur after vaccination and/or boosters is important for monitoring the impact of immunization campaigns. While COVID-19 vaccines are safe and effective, some cases are still expected in persons who have been vaccinated, as no vaccine is 100% effective. For more information, please see https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/COVID-19/Post-Vaccine-COVID19-Cases.aspx

Post-vaccination infection data is updated weekly and includes data on cases, hospitalizations, and deaths among the unvaccinated, those vaccinated with a primary series only, and those with an additional or booster dose. Partially vaccinated individuals are excluded. To account for reporting and processing delays, there is a 14 day lag in provided data (for example, for data through 1/23/2022, only data through 1/9/2022 will be made available). For deaths, there is an even greater lag in reporting, so more recent data should be used with caution. For display on the public dashboard, there is an additional 7-day lag for death data (21 days total). Note that this lag is separate from the difference in dates between data processing and updates to the website (in the above example, data through 1/9/2022 would be updated on the website on 2/2/2022).

Notes:

• On February 2, 2022, the post-vaccination data has been changed to distinguish between vaccination with a primary series only versus vaccinated and boosted. The previous dataset has been uploaded as an archived table. Additionally, the lag on this data has been extended to 14 days.

• On November 29, 2021, the denominator for calculating vaccine coverage has been changed from age 16+ to age 12+ to reflect new vaccine eligibility criteria. The previous dataset based on age 16+ denominators has been uploaded as an archived table.

Data for CDC’s COVID Data Tracker site on Rates of COVID-19 Cases and Deaths by Vaccination Status. Click 'More' for important dataset description and footnotes

Dataset and data visualization details: These data were posted on October 21, 2022, archived on November 18, 2022, and revised on February 22, 2023. These data reflect cases among persons with a positive specimen collection date through September 24, 2022, and deaths among persons with a positive specimen collection date through September 3, 2022.

Vaccination status: A person vaccinated with a primary series had SARS-CoV-2 RNA or antigen detected on a respiratory specimen collected ≥14 days after verifiably completing the primary series of an FDA-authorized or approved COVID-19 vaccine. An unvaccinated person had SARS-CoV-2 RNA or antigen detected on a respiratory specimen and has not been verified to have received COVID-19 vaccine. Excluded were partially vaccinated people who received at least one FDA-authorized vaccine dose but did not complete a primary series ≥14 days before collection of a specimen where SARS-CoV-2 RNA or antigen was detected. Additional or booster dose: A person vaccinated with a primary series and an additional or booster dose had SARS-CoV-2 RNA or antigen detected on a respiratory specimen collected ≥14 days after receipt of an additional or booster dose of any COVID-19 vaccine on or after August 13, 2021. For people ages 18 years and older, data are graphed starting the week including September 24, 2021, when a COVID-19 booster dose was first recommended by CDC for adults 65+ years old and people in certain populations and high risk occupational and institutional settings. For people ages 12-17 years, data are graphed starting the week of December 26, 2021, 2 weeks after the first recommendation for a booster dose for adolescents ages 16-17 years. For people ages 5-11 years, data are included starting the week of June 5, 2022, 2 weeks after the first recommendation for a booster dose for children aged 5-11 years. For people ages 50 years and older, data on second booster doses are graphed starting the week including March 29, 2022, when the recommendation was made for second boosters. Vertical lines represent dates when changes occurred in U.S. policy for COVID-19 vaccination (details provided above). Reporting is by primary series vaccine type rather than additional or booster dose vaccine type. The booster dose vaccine type may be different than the primary series vaccine type. ** Because data on the immune status of cases and associated deaths are unavailable, an additional dose in an immunocompromised person cannot be distinguished from a booster dose. This is a relevant consideration because vaccines can be less effective in this group. Deaths: A COVID-19–associated death occurred in a person with a documented COVID-19 diagnosis who died; health department staff reviewed to make a determination using vital records, public health investigation, or other data sources. Rates of COVID-19 deaths by vaccination status are reported based on when the patient was tested for COVID-19, not the date they died. Deaths usually occur up to 30 days after COVID-19 diagnosis. Participating jurisdictions: Currently, these 31 health departments that regularly link their case surveillance to immunization information system data are included in these incidence rate estimates: Alabama, Arizona, Arkansas, California, Colorado, Connecticut, District of Columbia, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Michigan, Minnesota, Nebraska, New Jersey, New Mexico, New York, New York City (New York), North Carolina, Philadelphia (Pennsylvania), Rhode Island, South Dakota, Tennessee, Texas, Utah, Washington, and West Virginia; 30 jurisdictions also report deaths among vaccinated and unvaccinated people. These jurisdictions represent 72% of the total U.S. population and all ten of the Health and Human Services Regions. Data on cases among people who received additional or booster doses were reported from 31 jurisdictions; 30 jurisdictions also reported data on deaths among people who received one or more additional or booster dose; 28 jurisdictions reported cases among people who received two or more additional or booster doses; and 26 jurisdictions reported deaths among people who received two or more additional or booster doses. This list will be updated as more jurisdictions participate. Incidence rate estimates: Weekly age-specific incidence rates by vaccination status were calculated as the number of cases or deaths divided by the number of people vaccinated with a primary series, overall or with/without a booster dose (cumulative) or unvaccinated (obtained by subtracting the cumulative number of people vaccinated with a primary series and partially vaccinated people from the 2019 U.S. intercensal population estimates) and multiplied by 100,000. Overall incidence rates were age-standardized using the 2000 U.S. Census standard population. To estimate population counts for ages 6 months through 1 year, half of the single-year population counts for ages 0 through 1 year were used. All rates are plotted by positive specimen collection date to reflect when incident infections occurred. For the primary series analysis, age-standardized rates include ages 12 years and older from April 4, 2021 through December 4, 2021, ages 5 years and older from December 5, 2021 through July 30, 2022 and ages 6 months and older from July 31, 2022 onwards. For the booster dose analysis, age-standardized rates include ages 18 years and older from September 19, 2021 through December 25, 2021, ages 12 years and older from December 26, 2021, and ages 5 years and older from June 5, 2022 onwards. Small numbers could contribute to less precision when calculating death rates among some groups. Continuity correction: A continuity correction has been applied to the denominators by capping the percent population coverage at 95%. To do this, we assumed that at least 5% of each age group would always be unvaccinated in each jurisdiction. Adding this correction ensures that there is always a reasonable denominator for the unvaccinated population that would prevent incidence and death rates from growing unrealistically large due to potential overestimates of vaccination coverage. Incidence rate ratios (IRRs): IRRs for the past one month were calculated by dividing the average weekly incidence rates among unvaccinated people by that among people vaccinated with a primary series either overall or with a booster dose. Publications: Scobie HM, Johnson AG, Suthar AB, et al. Monitoring Incidence of COVID-19 Cases, Hospitalizations, and Deaths, by Vaccination Status — 13 U.S. Jurisdictions, April 4–July 17, 2021. MMWR Morb Mortal Wkly Rep 2021;70:1284–1290. Johnson AG, Amin AB, Ali AR, et al. 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. MMWR Morb Mortal Wkly Rep 2022;71:132–138. Johnson AG, Linde L, Ali AR, et al. COVID-19 Incidence and Mortality Among Unvaccinated and Vaccinated Persons Aged ≥12 Years by Receipt of Bivalent Booster Doses and Time Since Vaccination — 24 U.S. Jurisdictions, October 3, 2021–December 24, 2022. MMWR Morb Mortal Wkly Rep 2023;72:145–152. Johnson AG, Linde L, Payne AB, et al. Notes from the Field: Comparison of COVID-19 Mortality Rates Among Adults Aged ≥65 Years Who Were Unvaccinated and Those Who Received a Bivalent Booster Dose Within the Preceding 6 Months — 20 U.S. Jurisdictions, September 18, 2022–April 1, 2023. MMWR Morb Mortal Wkly Rep 2023;72:667–669.

This table illustrates the effectiveness of vaccination by comparing the number of cases of six vaccine-preventable diseases in Canada before and after the introduction of each vaccine.

In the United States, influenza vaccination rates differ greatly by age. For example, during the 2022-2023 flu season, around ** percent of those aged 65 years and older received an influenza vaccination, compared to just ** percent of those aged 18 to 49 years. The CDC recommends that everyone six months and older in the United States should get vaccinated against influenza every year, with a few exceptions. Although influenza is mild for most people it can lead to hospitalization and even death, especially among the young, the old, and those with certain preexisting conditions. The impact of flu vaccinations Flu vaccinations are safe and effective, preventing thousands of illnesses, medical visits, and deaths every year. However, the effectiveness of flu vaccines varies each year depending on what flu viruses are circulating that season and the age and health status of the person receiving the vaccination. During the 2022-2023 flu season it was estimated that influenza vaccination prevented almost *********** hospitalizations among those aged 65 years and older. In addition, flu vaccinations prevented ***** deaths among those aged 65 years and older as well as ** deaths among children six months to four years. The burden of influenza The impact of influenza is different from season to season. However, during the 2022-2023 flu season there were around ** million cases of influenza in the United States. Furthermore, there were around ****** deaths due to influenza, an increase from the previous year but significantly fewer than in ********* when influenza contributed to ****** deaths. Most of these deaths are among the elderly. In ********* the death rate due to influenza among those aged 65 years and older was around **** per 100,000 population. In comparison, those aged 18 to 49 years had an influenza death rate of just ** per 100,000 population.

Additional file 3: Table S3. Vaccine booster effectiveness against viral variants. Studies of vaccine booster effectiveness against viral variants. Related to Table 2.

Parameter settings for simulations. This table contains the different values tested, resulting in a total of 64,000 simulations. The percent of the population vaccinated daily is an upper limit since only S, E, and R individuals could be vaccinated. Maximum efficacy refers to the probability that a vaccinated person is protected from getting infected 21 days after receiving the vaccine.

BackgroundDespite the rapid evolution of the SARS-CoV-2 viruses, vaccines targeting ancestral strains remain widely used. This study evaluates the effectiveness of ancestral strains inactivated and mRNA COVID-19 vaccine boosters in preventing fatal outcomes among severe COVID-19 cases during the circulation of the XBB and JN.1 variants.MethodsWe analyzed 2,157 severe COVID-19 cases (aged ≥50) reported to the Centre for Health Protection from the hospital authority-managed public hospitals between January 30, 2023, and January 29, 2024. Logistic regression was used to investigate the relationship between vaccination status and fatal outcomes, adjusting for age, sex, and residential status in residential care homes for the older adult (RCHE), and other demographic factors.ResultsAmong the 2,157 cases, 764 (35.4%) succumbed within a 28-day follow-up. Fatal outcomes were more common among older individuals, RCHE residents, and those unvaccinated or with incomplete initial vaccination (zero to two doses). Fewer deaths had received ancestral strains mRNA or inactivated booster doses compared to those not receiving booster. Univariate logistic regression revealed the lowest in-hospital mortality odds ratio for mRNA booster recipients, followed by inactivated booster recipients, and then those with completed initial vaccination (three doses). After adjusting for confounders, booster vaccination remained significantly associated with reduced in-hospital mortality.ConclusionVaccines based on ancestral strains maintain some degree of effectiveness against recently emerged variants, offering insights for healthcare policies in regions where earlier generations of inactivated and mRNA vaccines continue to be administered.