Number Needed To Vaccinate Research Articles

Health effects of routine measles vaccination and supplementary immunisation activities in 14 high-burden countries: a Dynamic Measles Immunization Calculation Engine (DynaMICE) modelling study

WHO recommends at least 95% population coverage with two doses of measles-containing vaccine (MCV). Most countries worldwide use routine services to offer a first dose of measles-containing vaccine (MCV1) and later, a second dose of measles-containing vaccine (MCV2). Many countries worldwide conduct supplementary immunisation activities (SIAs), offering vaccination to all people in a specific age range irrespective of previous vaccination history. We aimed to estimate the relative effects of each dose and delivery route in 14 countries with high measles burden. We used an age-structured compartmental dynamic model, the Dynamic Measles Immunization Calculation Engine (DynaMICE), to assess the effects of different vaccination strategies on measles susceptibility and burden during 2000-20 in 14 countries with high measles incidence (containing 53% of the global birth cohort and 78% of the global measles burden). Country-specific routine MCV1 and MCV2 coverage data during 1980-2020 were obtained from the WHO and UNICEF Estimates of National Immunization Coverage database for all modelled countries and SIA data were obtained from the WHO summary of measles and rubella SIAs. We estimated the incremental health effects of different vaccination strategies using prevented cases of measles and deaths from measles and their efficiency using the incremental number needed to vaccinate (NNV) to prevent an additional measles case. Compared with no vaccination, MCV1 implementation was estimated to have prevented 824 million cases of measles and 9·6 million deaths from measles, with a median NNV of 1·41 (IQR 1·35-1·44). Adding routine MCV2 to MCV1 was estimated to have prevented 108 million cases and 404 270 deaths, whereas adding SIAs to MCV1 was estimated to have prevented 256 million cases and 4·4 million deaths. Despite larger incremental effects, adding SIAs to MCV1 (median incremental NNV 6·02, 5·30-7·68) showed reduced efficiency compared with adding routine MCV2 (5·41, 4·76-6·11). Vaccination strategies, including non-selective SIAs, reach a greater proportion of children who are unvaccinated and reduce measles burden more than MCV2 alone, but efficiency is lower because of the wide age range targeted by SIAs. This analysis provides information to help improve the health effects and efficiency of measles vaccination strategies. The interplay between MCV1, MCV2, and SIAs should be considered when planning future measles vaccination strategies. Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation.

Number needed to vaccinate with a COVID-19 booster to prevent a COVID-19-associated hospitalization during SARS-CoV-2 Omicron BA.1 variant predominance, December 2021–February 2022, VISION Network: a retrospective cohort study

Understanding the usefulness of additional COVID-19 vaccine doses-particularly given varying disease incidence-is needed to support public health policy. We characterize the benefits of COVID-19 booster doses using number needed to vaccinate (NNV) to prevent one COVID-19-associated hospitalization or emergency department encounter. We conducted a retrospective cohort study of immunocompetent adults at five health systems in four U.S. states during SARS-CoV-2 Omicron BA.1 predominance (December 2021-February 2022). Included patients completed a primary mRNA COVID-19 vaccine series and were either eligible to or received a booster dose. NNV were estimated using hazard ratios for each outcome (hospitalization and emergency department encounters), with results stratified by three 25-day periods and site. 1,285,032 patients contributed 938 hospitalizations and 2076 emergency department encounters. 555,729 (43.2%) patients were aged 18-49 years, 363,299 (28.3%) 50-64 years, and 366,004 (28.5%) ≥65 years. Most patients were female (n=765,728, 59.6%), White (n=990,224, 77.1%), and non-Hispanic (n=1,063,964, 82.8%). 37.2% of patients received a booster and 62.8% received only two doses. Median estimated NNV to prevent one hospitalization was 205 (range 44-615) and NNV was lower across study periods for adults aged ≥65 years (110, 46, and 88, respectively) and those with underlying medical conditions (163, 69, and 131, respectively). Median estimated NNV to prevent one emergency department encounter was 156 (range 75-592). The number of patients needed to receive a booster dose was highly dependent on local disease incidence, outcome severity, and patient risk factors for moderate-to-severe disease. Funding was provided by the Centers for Disease Control and Prevention though contract 75D30120C07986 to Westat, Inc. and contract 75D30120C07765 to Kaiser Foundation Hospitals.

Comparative effectiveness of the sars-CoV-2 vaccines during delta dominance

BackgroundSeveral vaccines with demonstrated efficacy for coronavirus disease 2019 (Covid-19) are available. The purpose of this study was to evaluate the COVID mRNA based and adenovector based vaccines’ differential effectiveness during the time of circulation of the Delta variant and determine what impact this would have on population health and cost effectiveness. MethodsWe used de-identified claims in a research database that included vaccination status and Covid-positivity status. Individuals ≥18 years, fully vaccinated with Ad26.COV2·S/J&J/Janssen, mRNA-1273/Moderna, or BNT162b2/Pfizer-BioNTech by September 30, 2021, were included. Outcomes were SARS-CoV-2-infection, emergency department visits, outpatient visits, inpatient hospitalizations, intensive care unit (ICU) transfers, death, and hospice transfers through September 30, 2021. ResultsAmong ∼6.5 million fully vaccinated individuals in the UHC Medicare Advantage and our commercially insured research database, mRNA-1273 performed better than BNT162b2 for infection, composite-hospitalization (hospitalization/ICU transfer/hospice transfer/death), and composite-ICU transfer (ICU transfer/hospice transfer/death) caused by B.1.612.7 (delta) variant infection. 26 CE.COV2.S performed worse than BNT162b2 for infection, composite-hospitalization, and composite-ICU transfers. The number needed to vaccinate (NNV) with mRNA1273 to prevent one hospitalization at 90 days was 3130 compared to 26 CE.COV2·S and 15,472 compared to BNT162b2. The NNV with mRNA1273 to prevent one ICU transfer at 90 days was 6358 compared to 26 CE.COV2·S and 34,279 compared to BNT162b2. For every one million individuals vaccinated with BNT162b compared to mRNA-1273, the approximate incremental inpatient cost would be $405,000 and the approximate incremental ICU cost would be $662,000. ConclusionsThe two-dose mRNA vaccines' effectiveness significantly exceeded the single-dose Ad26.COV2·S vaccine's effectiveness from population health and cost-effectiveness perspectives. The mRNA1273 vaccine showed slightly more effectiveness than the BNT162b vaccine.

The impact of influenza vaccination on surgical outcomes in COVID-19 positive patients: An analysis of 43,580 patients.

Multiple recent studies suggest a possible protective effect of the influenza vaccine against severe acute respiratory coronavirus 2 (SARS-CoV-2). This effect has yet to be evaluated in surgical patients. This study utilizes a continuously updated federated electronic medical record (EMR) network (TriNetX, Cambridge, MA) to analyze the influence of the influenza vaccine against post-operative complications in SARS-CoV-2-positive patients. The de-identified records of 73,341,020 patients globally were retrospectively screened. Two balanced cohorts totaling 43,580 surgical patients were assessed from January 2020-January 2021. Cohort One received the influenza vaccine six months-two weeks prior to SARS-CoV-2-positive diagnosis, while Cohort Two did not. Post-operative complications within 30, 60, 90, and 120 days of undergoing surgery were analyzed using common procedural terminology(CPT) codes. Outcomes were propensity score matched for characteristics including age, race, gender, diabetes, obesity, and smoking. SARS-CoV-2-positive patients receiving the influenza vaccine experienced significantly decreased risks of sepsis, deep vein thrombosis, dehiscence, acute myocardial infarction, surgical site infections, and death across multiple time points(p<0.05, Bonferroni Correction p = 0.0011). Number needed to vaccinate (NNV) was calculated for all significant and nominally significant findings. Our analysis examines the potential protective effect of influenza vaccination in SARS-CoV-2-positive surgical patients. Limitations include this study's retrospective nature and reliance on accuracy of medical coding. Future prospective studies are warranted to confirm our findings.

116. Potential Clinical Impact of Respiratory Syncytial Virus (RSV) Vaccination in Older Adults in the United States

Abstract Background RSV causes acute respiratory disease (ARD), including severe lower respiratory tract disease (LRTD) in older adults, which can lead to hospitalization and death. Currently, there are no vaccines approved to prevent RSV disease. This study estimated the potential clinical impact of a hypothetical RSV vaccine over a 1-year time horizon in older adults aged ≥ 60 years. Methods A decision-analytic model was developed (Figure 1). A strategy was used where the entire US population aged ≥ 60 years was given a single dose vaccine with an assumed efficacy of 75% against ARD, LRTD, and LRTD-hospitalizations and compared to a population who did not receive a vaccine. Given the uncertainty around RSV hospitalization rates, 2 base-case scenarios were created: (1) hospitalization rates that used RSV-specific claim codes and (2) hospitalization rates increased by 49% to account for underreporting in claims; Table 1 shows key inputs. One-way sensitivity analyses were used to assess the impact of specific parameter estimates. Results The vaccine would prevent 1.8 million and 0.6 million upper respiratory disease and LRTD cases, respectively; Figure 2 shows additional results for both base-case scenarios. The number needed to vaccinate (NNV) to prevent 1 LRTD case is 119; the NNV to prevent 1 LRTD hospitalization or death ranges from 792 to 1180 and 10,452 to 15,574, respectively. Sensitivity analyses indicate that results mainly depend on vaccine efficacy, and incidence of ARD and LRTD. Conclusion There is substantial US public health benefit associated with utilization of an effective RSV vaccine in individuals ≥ 60 years of age to reduce RSV-associated morbidity and mortality; however, the magnitude of impact depends on RSV epidemiology, which is still being defined for older adults. Several model parameters were based on assumptions, and robust evidence generation is needed including the efficacy of an RSV vaccine, which is an important consideration in assessing the impact of vaccination in this age group. Disclosures Kelly Fust, MS, Quadrant Health Economics Inc: Contractor at Quadrant Health Economics Inc who was funded by Moderna to perform this study Michele Kohli, PhD, Quadrant Health Economics Inc: Shareholder at Quadrant Health Economics Inc who was funded by Moderna to perform this study|Quadrant Health Economics Inc: Stocks/Bonds Catherine A. Panozzo, PhD, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds Philip Buck, PhD, MPH, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds Parinaz Ghaswalla, PhD, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds.

Protective effects of prior third dose mRNA vaccination in rural nursing home residents during SARS-CoV-2 outbreaks.

BackgroundIn Canada, mortality due to SARS‐CoV‐2 disproportionately impacted residents of nursing homes (NH). In November 2021, NH residents in the Canadian province of Manitoba became eligible to receive three doses of mRNA vaccine but coverage with three doses has not been universal. The objective of this study was to compare the protection from infection conferred by one, two, and three doses of COVID‐19 mRNA vaccine compared to no vaccination among residents of nursing homes experiencing SARS‐CoV‐2 outbreaks.MethodsInfection Prevention and Control reports from 8 rural nursing homes experiencing outbreaks of SARS‐CoV‐2 between January 6, 2022, and March 5, 2022, were analyzed. Attack rates and the number needed to vaccinate (NNV) were calculated.ResultsSARS‐CoV‐2 attack rate was 65% among NH residents not vaccinated, 58% among residents who received 1–2 doses of mRNA COVID‐19 vaccine, and 28% among residents who had received 3 vaccine doses. The NNV to prevent one nursing home resident from SARS‐CoV‐2 infection during an outbreak was 3 for a vaccination with 3 doses and 14 for 1–2 doses of COVID‐19 mRNA vaccine. The superiority of receiving the third dose was statistically significant compared to 1–2 doses (Chi‐Squared, p < 0.00001).ConclusionsNursing home residents who received three doses of COVID‐19 mRNA vaccine were at lower risk of SARS‐CoV‐2 infection compared to those who received 1–2 doses. Our analyses lend support to the protective effects of the third dose of mRNA vaccine for NH residents in the event of a SARS‐CoV‐2 outbreak.

Duration of COVID-19 mRNA Vaccine Effectiveness against Severe Disease.

Waning immunity following administration of mRNA-based COVID-19 vaccines remains a concern for many health systems. We undertook a study to determine if recent reports of waning for severe disease could have been attributed to design-related bias by conducting a study only among those detected with a first SARS-CoV-2 infection. We used a matched case-control study design with the study base being all individuals with first infection with SARS-CoV-2 reported in the State of Qatar between 1 January 2021 and 20 February 2022. Cases were those detected with first SARS-CoV-2 infection requiring intensive care (hard outcome), while controls were those detected with first SARS-CoV-2 infection who recovered without the need for intensive care. Cases and controls were matched in a 1:30 ratio for the calendar month of infection and the comorbidity category. Duration and magnitude of conditional vaccine effectiveness against requiring intensive care and the number needed to vaccinate (NNV) to prevent one more case of COVID-19 requiring intensive care was estimated for the mRNA (BNT162b2/mRNA-1273) vaccines. Conditional vaccine effectiveness against requiring intensive care was 59% (95% confidence interval (CI), 50 to 76) between the first and second dose, and strengthened to 89% (95% CI, 85 to 92) between the second dose and 4 months post the second dose in persons who received a primary course of the vaccine. There was no waning of vaccine effectiveness in the period from 4 to 6, 6 to 9, and 9 to 12 months after the second dose. This study demonstrates that, contrary to mainstream reports using hierarchical measures of effectiveness, conditional vaccine effectiveness against requiring intensive care remains robust till at least 12 months after the second dose of mRNA-based vaccines.

406 SARS-CoV-2 Vaccination Modelling for Safe Surgery to Save Lives: Data from an International Prospective Cohort Study

AimPreoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling.MethodThe primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty.ResultsNNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year.ConclusionsAs global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.

The risk-benefit ratio of Covid-19 vaccines: Publication policy by retraction does nothing to improve it.

On June 24, 2021 we published a risk-benefit analysis of COVID-19 vaccines, admittedly based on a shaky database. This analysis resulted in the insight, that very likely for three deaths prevented by vaccination we will have to accept that about two people die as a consequence of these vaccinations.1 This analysis led to editors’ threatening to withdraw, and the journal indeed retracted the publication. After a thorough re-review, it was republished.2, 3 The database we based our analysis on was a large naturalistic study of the BioNTech vaccine in Israel.4 This was the only study at the time that allowed for a direct estimation of an absolute risk reduction (ARR) in mortality. Admittedly, the ARR estimate was only available for a short observation period of 4 weeks after the first vaccine dose, a point raised by critics. One might have wanted a longer observation period to bring out the benefit of vaccinations more clearly, and our estimate of a number needed to vaccinate (NNV) of 16 000 to prevent one death might have been overly conservative. The recently published 6-month interim report of the BioNTech-regulatory clinical trial now covers a period long enough to let us look at this risk benefit ratio once again.5 In Table S4 of this publication,5 14 deaths are reported in the placebo group (n = 21 921) and 15 in the vaccination group (n = 21 926). Among them, two deaths in the placebo-group were attributed to COVID-19, and one in the vaccination group was attributed to COVID-19 pneumonia. This leads to an ARR = 4.56 × 10–5, and conversely to an NNV = 1/ARR = 21 916 to prevent one death by COVID-19. This shows that our original estimate was not so far off the mark. These passive pharmacovigilance data, different from the active reporting system of trials and observations, are notorious for underestimating casualties and side effects.6 Other severe side effects occur, such as myocarditis in young males who according to a recent study suffer a 13.6 fold risk of myocarditis.7 Thus, we have novel and worrying data that confirm the analysis we published in summer 2021, urging us to repeat our call for an installment of a European-wide active monitoring system that documents the safety and efficacy of COVID-19 vaccines long-term and for a rational public debate about the risk-benefit ratio of these novel vaccines. The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

The Number Needed to Vaccinate (NNV) against herpes zoster: a systematic review with meta-analysis

Objectives The number needed to vaccinate (NNV) quantifies the effectiveness of vaccination programs. We summarised the published data on NNV against herpes zoster to inform vaccination policies. Methods We systematically identified studies based on a priori established and registered methods. The main outcomes were the NNV against herpes zoster infection, hospitalisation and mortality. Where appropriate, we conducted meta-analyses using inverse variance, random-effects models, pooling estimated NNV with associated 95% confidence interval (CI). Statistical heterogeneity between pooled estimates was calculated using the I 2 statistic. Results Out of 229 unique citations, we included eight nonrandomized studies. Among 50+ year-olds, the NNV against herpes zoster infection using the recombinant subunit vaccine was 11 (95%CI 8–14; I 2 = 0%; 3 studies) and variable (I2 = 94.4%; 7 studies) using live attenuated vaccine, ranging from 10 (95%CI 1–19) to 58 (95%CI 49–67). Among 65+ year-olds, the NNV against herpes zoster infection using the recombinant subunit vaccine was 12 (95%CI: 9–15; I 2 = 0%; 2 studies) and variable (I2 = 98.5%; 4 studies) using live attenuated vaccine, ranging from 14 (95%CI 5–23) to 75 (95%CI 66–84). The NNV against herpes zoster hospitalisation among 65+ year-olds using the live attenuated vaccine was 280 (95%CI 209–352; I2 = 0%; 2 studies). There was a paucity of data to inform other meta-analyses. Conclusion Evidence on the NNV against herpes zoster is scarce. Vaccination with the recombinant subunit herpes zoster vaccine may be more effective than with the live attenuated vaccine in preventing infection among 50+ year-olds. More studies are needed for a stronger evidence base for decision-making.

Seasonal influenza vaccination is associated with reduced risk of death among Medicare beneficiaries☆

BackgroundInfluenza causes substantial mortality, especially among older persons. Influenza vaccines are rarely more than 50% effective and rarely reach more than half of the US Medicare population, which is primarily an aged population. We wished to estimate the association between vaccination and mortality reduction. MethodWe used the US Center for Medicare and Medicaid Services (CMS) DataLink Project to determine vaccination status and timing during the 2017–2018 influenza season for more than 26 million Medicare enrollees. Patient-level demographic, health, co-morbidity, hospitalization, vaccination, and healthcare utilization claims data were supplied as covariates to general linear models in order to isolate and estimate the association between participation in the vaccination program and relative risk of death. FindingsThe 2017–2018 seasonal influenza vaccine reduced (Relative Risk Ratio [RRR] 0.936 [95% CI = 0.918–0.954]) the risk of all-cause death among beneficiaries following a hospitalization for sepsis and moreover the risk of death without a prior hospitalization during the 2.5-month outcome window (RRR 0.870 [95% CI = 0.853–0.887]). We estimate the number needed to vaccinate (NNV) to prevent a death in the ten-week outcome window is between 1,515 beneficiaries (95% CI = 1,351–1,754; derived from the average treatment effect of augmented inverse probability weighting) and 1,960 beneficiaries (95% CI = 1,695–2,381; derived from the average marginal effect of logistic regression). Among beneficiaries requiring hospitalization, the greatest death risk reduction accrued to those 85 + years of age who were hospitalized with sepsis, RRR 0.92 [95% CI = 0.89–0.95]. No apparent benefit was realized by beneficiaries who required custodial (nursing home) care. InterpretationSeasonal influenza immunization is associated with relative reduction of death risk among non-institutionalized Medicare beneficiaries. FundingAll authors are full-time or contractual employees of the United States Federal Government, Department of Health and Human Services, the funding agency.

Retracted: The Safety of COVID-19 Vaccinations-We Should Rethink the Policy.

Background: COVID-19 vaccines have had expedited reviews without sufficient safety data. We wanted to compare risks and benefits. Method: We calculated the number needed to vaccinate (NNTV) from a large Israeli field study to prevent one death. We accessed the Adverse Drug Reactions (ADR) database of the European Medicines Agency and of the Dutch National Register (lareb.nl) to extract the number of cases reporting severe side effects and the number of cases with fatal side effects. Result: The NNTV is between 200–700 to prevent one case of COVID-19 for the mRNA vaccine marketed by Pfizer, while the NNTV to prevent one death is between 9000 and 50,000 (95% confidence interval), with 16,000 as a point estimate. The number of cases experiencing adverse reactions has been reported to be 700 per 100,000 vaccinations. Currently, we see 16 serious side effects per 100,000 vaccinations, and the number of fatal side effects is at 4.11/100,000 vaccinations. For three deaths prevented by vaccination we have to accept two inflicted by vaccination. Conclusions: This lack of clear benefit should cause governments to rethink their vaccination policy.

Patients who will undergo elective inpatient surgery as a priority group to receive vaccination against SARS-CoV-2.

Patients who will undergo elective inpatient surgery as a priority group to receive vaccination against SARS-CoV-2.

Efficacy of HPV vaccination among seropositive, DNA negative cohorts.

10552 Background: Prophylactic HPV vaccination of naïve cohorts is known to be highly effective in the prevention of incident HPV infection and HPV-associated cervical premalignancy. Conversely, vaccination of women with active (DNA+) HPV infections has been demonstrated to be ineffective. Vaccine efficacy among previously exposed, but currently uninfected women, i.e. those who have serological evidence of a prior HPV infection without corresponding detectable HPV DNA, remains incompletely defined. This meta-analysis assessed the serotype-specific efficacy of prophylactic HPV vaccination against HPV16/18 persistent infection (PI) and cervical intraepithelial neoplasia (CIN) among seropositive, DNA negative (SPDN) women enrolled to RCTs of HPV L1-based vaccines. Methods: The study protocol was prospectively registered on PROSPERO (CRD42020206888). Searches were conducted on 08/16/20 on MEDLINE, EMBASE, SCOPUS and CENTRAL. RCTs of L1-based prophylactic bivalent or quadrivalent HPV vaccines, reporting serotype-specific clinical efficacy endpoints in the HPV16/18 seropositive, DNA-negative populations were included. Two authors independently screened studies, extracted data and assessed for bias. Data for SPDN women were extracted from subgroup analyses within primary and secondary publications, publication supplements, and manufacturers' clinical study reports. Relative risks (RR) of 6-month persistent infection (6mPI), 12-month persistent infection (12mPI), CIN1+ and CIN2+ were pooled using a random-effects model. Results: A total of 1727 citations were reviewed. 8 studies, with a total of 9569 SPDN participants, met all eligibility criteria. The relative risk of 6mPI (RR: 0.22, 95% CI 0.08-0.61, p = 0.018), 12mPI (RR: 0.20, 95% CI 0.05-0.80, p = 0.035), CIN1+ (RR:0.13, 95% CI 0.05-0.30, p = 0.003) and CIN2+ (RR: 0.15, 95% CI 0.04-0.59, p = 0.022) was significantly reduced in the vaccinated compared to the unvaccinated group. The number needed to vaccinate (NNV) to prevent one case of CIN1+ and CIN2+ was 152 and 208 respectively. Conclusions: Our findings suggest high serotype-specific efficacy for HPV vaccination among cohorts of women with evidence of prior HPV 16/18 infections. Women without DNA evidence of active infection may be seronegative, implying naïve status and &gt; 99% efficacy; or seropositive, implying SPDN status and 87% efficacy against CIN1+ for HPV 16/18. Women without DNA evidence of HPV 16/18 infection should be offered prophylactic HPV vaccination regardless of prior exposure history.

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study.

BackgroundPreoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling.MethodsThe primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty.ResultsNNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year.ConclusionAs global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.

Impact of national influenza vaccination strategy in severe influenza outcomes among the high-risk Portuguese population

BackgroundAll aged individuals with a chronic condition and those with 65 and more years are at increased risk of severe influenza post-infection complications. There is limited research on cases averted by the yearly vaccination programs in high-risk individuals. The objective was to estimate the impact of trivalent seasonal influenza vaccination on averted hospitalizations and death among the high-risk population in Portugal.MethodsThe impact of trivalent seasonal influenza vaccination was estimated using vaccine coverage, vaccine effectiveness and the number of influenza-related hospitalizations and deaths. The number of averted events (NAE), prevented fraction (PF) and number needed to vaccinate (NVN) were estimated for seasons 2014/15 to 2016/17.ResultsThe vaccination strategy averted on average approximately 1833 hospitalizations and 383 deaths per season. Highest NAE was observed in the ≥65 years population (85% of hospitalizations and 95% deaths) and in the 2016/17 season (1957 hospitalizations and 439 deaths). On average, seasonal vaccination prevented 21% of hospitalizations in the population aged 65 and more, and 18.5% in the population with chronic conditions. The vaccination also prevented 29% and 19.5% of deaths in each group of the high-risk population. It would be needed to vaccinate 3360 high-risk individuals, to prevent one hospitalization and 60,471 high-risk individuals to prevent one death.ConclusionThe yearly influenza vaccination campaigns had a sustained positive benefit for the high-risk population, reducing hospitalizations and deaths. These results can support public health plans toward increased vaccine coverage in high-risk groups.

2727. Numbers Needed to Vaccinate for Prevention of Adult Pneumonia with Pneumococcal Conjugate Vaccine: Which Values Should Determine Policy?

BackgroundAt the meeting of the Advisory Committee on Immunization Practices (ACIP) on February 28, 2019, the US Centers for Disease Control and Prevention (CDC) and the Pneumococcal Work Group (PWG) presented data to inform the public health question of whether the 13-valent pneumococcal conjugate vaccine (PCV13) should continue to be recommended for routine immunization of all adults age 65 years and older in the United States.MethodsWe reviewed all three available studies reporting adult PCV13 vaccine effectiveness against all-cause pneumonia, calculated numbers needed to vaccinate (NNV), and compared these results to NNV data presented to the ACIP based on etiologically and radiologically confirmed vaccine-type (VT) disease. Studies included a randomized controlled trial of inpatient pneumonia among Dutch persons age 65+ years, a US CDC-led observational study among the US Medicare population of inpatient pneumonia, and an observational study of inpatient and outpatient pneumonia in Germany.ResultsBased on a background incidence of etiologically and radiologically confirmed VT community-acquired pneumonia of 17–76 per 100,000 per year and PCV13 VE of 43%, the CDC presented to ACIP an annual NNV estimate for preventing one pneumonia case of 3,000 to 14,000. For the three studies we reviewed, VEs were 6% to 12% against all-cause pneumonia and background all-cause pneumonia incidences were 891 to 1776 per 100,000 per year. Assuming a 5-year PCV13 duration of protection, for these three studies NNVs to prevent a case of pneumonia were 95 to 277, or 11- to 147-fold lower than what was presented at ACIP.ConclusionTo avoid inaccurate conclusions for potentially efficient interventions, calculations of NNVs, rate reductions, and economic benefits should include sensitive outcomes, such as all-cause pneumonia, in addition to more specific but lower sensitivity outcomes such as VT, radiologically confirmed pneumonia.Disclosures All authors: No reported disclosures.

Effectiveness and cost-effectiveness of vaccination against herpes zoster in Canada: a modelling study.

Two vaccines against herpes zoster are currently authorized for use in Canada: the recombinant subunit zoster vaccine and live attenuated zoster vaccine. We compared the effectiveness and cost-effectiveness of these 2 vaccines. We used a decision analytic static cohort model parametrized with Canadian epidemiologic and economic data. We performed the economic analysis from the health care system perspective, using a lifetime horizon and a 3% discount rate for costs and benefits. The primary outcome was the incremental cost per quality-adjusted life-year (QALY) gained, relative to no vaccination. We ran 30 000 simulations varying all model parameters, including vaccine costs, efficacy and waning. The number needed to vaccinate (NNV) was higher for the live attenuated zoster vaccine than for the recombinant subunit zoster vaccine for all herpes zoster-related events at all ages. For example, in persons exactly 65 years old, for herpes zoster, median NNV was 21 (90% uncertainty interval [UI] 13-31) versus 8 (90% UI 6-18), and for postherpetic neuralgia, NNV was 64 (90% UI 33-93) versus 31 (90% UI 23-73). For the recombinant vaccine, the median cost-effectiveness ratios varied between cost-saving and $25 881 per QALY gained for adults aged 50 years or older. For the live vaccine, the cost-effectiveness ratios varied between cost-saving and $130 587 per QALY gained and were less than $45 000 per QALY gained only for those 65 to 75 years old. Given its higher efficacy, we estimated that the cost for the complete series of the recombinant vaccine could be $150 to $200 more than the cost of the live vaccine and still be considered cost-effective. Our model predicted that the recombinant subunit zoster vaccine is likely cost-effective in Canada for adults 60 years or older, and is likely more cost-effective than live attenuated zoster vaccine. These results have informed updated national and provincial recommendations on herpes zoster vaccination.

Influenza syndromic surveillance and vaccine efficacy in the UK Armed Forces, 2017–2018

IntroductionThis paper describes the first ever analysis of health data to report influenza vaccine uptake and the effectiveness of the vaccine in preventing general practice presentations for influenza-like illness (ILI)...

Age-targeted tuberculosis vaccination in China and implications for vaccine development: a modelling study.

Tuberculosis is the leading single-pathogen cause of death worldwide, and China has the third largest number of cases worldwide. New tools, such as new vaccines, are needed to meet WHO tuberculosis goals. Tuberculosis vaccine development strategies mostly target infants or adolescents, but given China's ageing epidemic, vaccinating older people might be important. We modelled the potential impact of new tuberculosis vaccines in China targeting adolescents (15-19 years) or older adults (60-64 years) with varying vaccine characteristics to inform strategic vaccine development. A Mycobacterium tuberculosis transmission model was calibrated to age-stratified demographic and epidemiological data from China. Varying scenarios of vaccine implementation (age targeting [adolescents or older adults] and coverage [30% or 70%]) and characteristics (efficacy [40%, 60%, or 80%], duration of protection [10 years or 20 years], and host infection status required for efficacy [pre-infection, post-infection in latency, post-infection in latency or recovered, or pre-infection and post-infection]) were assessed. Primary outcomes were tuberculosis incidence and mortality rate reduction in 2050 in each vaccine scenario compared with the baseline (no new vaccine) scenario and cumulative number needed to vaccinate (NNV) per case or death averted, 2025-50. By 2050, results suggest that 74·5% (uncertainty interval [UI] 70·2-78·6) of incident tuberculosis cases in China would occur in people aged 65 years or older, and 75·1% (66·8-80·7) of all cases would be due to reactivation, rather than new infection. All vaccine profiles delivered to older adults had higher population-level impact (reduction of incidence and mortality rates) and lower NNV per case and per death averted than if delivered to adolescents. For an intermediate vaccine scenario of 60% efficacy, 10-year protection, and 70% coverage, the reduction of tuberculosis incidence rates with older adult vaccination was 1·9 times (UI 1·5-2·6) to 157·5 times (119·3-225·6) greater than with adolescent vaccination, and the NNV was 0·011 times (0·008-0·014) to 0·796 times (0·632-0·970) lower. Furthermore, with older adult vaccination, post-infection vaccines provided substantially greater mortality and incidence rate reductions than pre-infection vaccines. Adolescent-targeted tuberculosis vaccines, the focus of many development plans, would have only a small impact in ageing, reactivation-driven epidemics such as those in China. Instead, an efficacious post-infection vaccine delivered to older adults will be crucial to maximise population-level impact in this setting and would provide an important contribution towards achieving WHO goals. Older adults should be included in tuberculosis vaccine clinical development and implementation planning. Aeras and UK MRC.