Emerging heterologous mRNA-based booster strategies within the COVID-19 vaccine landscape

Messenger RNA (mRNA)-based vaccine platforms used for the development of mRNA-1273 and BNT162b2 have provided a robust adaptable approach to offer protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, as variants of concern (VoCs), such as omicron and associated sub-variants, emerge, boosting strategies must also adapt to keep pace with the changing landscape. Heterologous vaccination regimens involving the administration of booster vaccines different than the primary vaccination series offer a practical, effective, and safe approach to continue to reduce the global burden of coronavirus disease 2019 (COVID-19). To understand the immunogenicity, effectiveness, and safety of heterologous mRNA-based vaccination strategies, relevant clinical and real-world observational studies were identified and summarized. Overall, heterologous boosting strategies with mRNA-based vaccines that are currently available and those in development will play an important global role in protecting individuals from COVID-19 caused by emerging VoCs.

An open-label, single-arm study evaluating the immunogenicity and safety of the hepatitis B vaccine HepB-CpG (HEPLISAV-B®) in adults receiving hemodialysis

BACKGROUND

Hemodialysis patients are at increased risk of hepatitis B virus (HBV) infection and are poorly responsive to HBV vaccines. Current vaccine recommendations for hemodialysis patients utilize more than twice the amount of hepatitis B surface antigen (HBsAg) used for healthy adults and achieve lower immune responses.

METHODS

An open-label, single-arm, multicenter trial was conducted among adults 18 years of age and older who were initiating or undergoing hemodialysis who had not previously received hepatitis B vaccine. Participants received four doses of HepB-CpG (HEPLISAV-B®) (20 mcg rHBsAg + 3000 mcg CpG 1018, a Toll-like receptor 9 agonist) administered at 0, 4, 8, and 16 weeks. Participants are being followed for 68 weeks. This paper reports the final immunogenicity analysis of the primary endpoint at study week 20 and an interim safety analysis.

RESULTS

We enrolled 119 participants receiving hemodialysis who were followed for a median of 47.4 weeks. Of the 119 participants, 75 were in the per-protocol population. At week 20, the seroprotection rate (% with antibodies to hepatitis B surface antigen [anti-HBs] ≥ 10 mIU/mL) was 89.3% and the percentage of participants with anti-HBs ≥ 100 mIU/mL was 81.3%. The anti-HBs geometric mean concentration was 1061.8 mIU/mL. HepB-CpG was well tolerated with no observed safety concerns.

CONCLUSION

In patients receiving hemodialysis, HepB-CpG given as four doses was well tolerated and induced very high anti-HBs concentrations and seroprotection in a very high proportion of recipients.

How New Models Of Vaccine Development For COVID-19 Have Helped Address An Epic Public Health Crisis

Coronavirus disease 2019 (COVID-19) vaccine development and manufacturing have proceeded at a historically unprecedented pace. This speed may be accounted for by the unprecedented scale of resources being devoted to addressing COVID-19; an unusual intensity of cooperation, encompassing the public and private sectors and occurring both within and across national borders; and innovation with respect to both technologies (for example, new vaccine platforms) and processes (for example, vaccine clinical trials). In this article we describe and analyze how resources, cooperation, and innovation have contributed to the accelerated development of COVID-19 vaccines. Similar levels and types of public investment, models of cooperation, and harnessing of innovative processes and technologies could be applied to future epidemics and other global health challenges.

286. Hepatitis B Vaccine Compliance: Comparing 2-Dose and 3-Dose Vaccines

Background

Less than 1 in 3 US adults who initiated the 3-dose (0, 1, 6 months) hepatitis B vaccine series have completed it. HepB-CpG (Heplisav-B; Dynavax) is a new licensed adjuvanted vaccine that requires only 2 doses (0, 1 month). As part of a cluster study performed at Kaiser Permanente Southern California, we compared compliance with second dose and series completion for HepB-CpG vs. comparator vaccine (Engerix-B; GlaxoSmithKline) recipients.

Methods

The cohort included adults not on dialysis who received their first dose of hepatitis B vaccine in family or internal medicine departments from 8/7/2018 to 2/1/2019. Second dose compliance was assessed for the full cohort, but series completion was assessed for a subset vaccinated from August 7, 2018 to September 30, 2018 to allow at least 6 months’ follow-up. Compliance rates were estimated using the Kaplan Meier method. Adjusted hazard ratios (aHR) were estimated using Cox proportional hazard regression with robust variance to account for within medical center correlation, adjusting for age, race/ethnicity, census block income and education, prior healthcare utilization, and factors that trigger alerts for hepatitis B vaccination (diabetes and testing for sexually transmitted infections).

Results

There were 6500 HepB-CpG and 7733 comparator vaccine recipients (1,442 and 2,604 prior to September 30, 2018). Rates of second dose compliance at 60 days were 32.9% for HepB-CpG and 29.1% for comparator vaccine, and rates of series completion at 210 days were 56.9% and 20.6%. There was no significant difference in second dose compliance (aHR 1.14, 95% CI: 0.91, 1.47), but HepB-CpG recipients were 5 times more likely to complete the series (aHR 5.17; 95% CI: 3.84, 6.98). Second dose compliance and series completion were significantly less likely among Blacks compared with Whites and significantly more likely among Asians, adults ≥60 years compared with those < 30 years, and adults living in census blocks with a median annual income of $40,000–69,000 compared with < $40,000.

Conclusion

Overall, second dose compliance was similar, but series completion was better for HepB-CpG recipients than comparator vaccine recipients, suggesting that the 2-dose vaccine could lead to improvements in coverage and protection against hepatitis B virus.

Disclosures

All authors: No reported disclosures.

Immunogenicity and safety of a 2-dose hepatitis B vaccine, HBsAg/CpG 1018, in persons with diabetes mellitus aged 60-70 years

BACKGROUND

Hepatitis B virus (HBV) remains a major public health issue, although it is a vaccine-preventable disease. Adults with diabetes are at greater risk of contracting HBV than the general population. Commonly used 3-dose HBV vaccines have reduced immunogenicity in older individuals and in those with diabetes mellitus.

METHODS

In this post hoc analysis of a phase 3 clinical trial, participants with type 2 diabetes mellitus aged 60-70 years received either 2-dose HBsAg/CpG 1018 (HEPLISAV-B®, n = 327) at 0 and 4 weeks and placebo at 24 weeks or 3-dose HBsAg/alum (Engerix-B®, n = 153) at 0, 4, and 24 weeks. Immunogenicity, including seroprotection rate (SPR) at week 28, and safety were assessed by subgroup (sex, body mass index, and smoking status). SPR was defined as antibody against hepatitis B surface antigen serum concentration ≥10 mIU/mL.

RESULTS

The SPR at week 28 was significantly higher with HBsAg/CpG 1018 (85.8% [235/274]) than with HBsAg/alum (58.5% [76/130]) in the per-protocol analysis, for an overall difference of 27.3% (95% CI, 18.0-36.8). SPRs with HBsAg/CpG 1018 were consistently markedly higher compared with HBsAg/alum, regardless of sex, body mass index, or smoking status. Adverse events and deaths were comparable between groups.

CONCLUSIONS

Two-dose HBsAg/CpG 1018 provides a higher level of seroprotection against HBV than does a 3-dose vaccine (HBsAg/alum) with a similar safety profile in patients aged 60-70 years with type 2 diabetes mellitus. Study identifier: NCT02117934.

2287. Recently Approved HEPLISAV-B(R) [Hepatitis B Vaccine (Recombinant), Adjuvanted] Shows a Higher Proportion of Subjects Achieving Seroprotection With a More Consistent Immune Response Compared With Engerix-B(R) [Hepatitis B Vaccine (Recombinant)] in Three Comparative Trials

Background

HEPLISAV-B^® [hepatitis B vaccine (recombinant), adjuvanted] uses a cytidine phospho-guanosine (CpG) oligonucleotide or “1018,” a Toll-like receptor 9 agonist, as an adjuvant. Engerix-B^® [hepatitis B vaccine (recombinant)], as well as other hepatitis B vaccines, use alum. HEPLISAV-B, a 2-dose vaccine given at Weeks 0 and 4, was recently approved for use in adults ≥18 years for the prevention of hepatitis B. Approval of HEPLISAV-B was based on three pivotal phase 3 noninferiority trials, comparing it with Engerix-B, a 3-dose vaccine given at Day 0, Day 30, and 6 months. Immunogenicity and safety results for these trials, HBV-10, HBV-16 and HBV-23, have been published previously; the safety of HEPLISAV-B was generally similar to Engerix-B.

Methods

The 3 randomized trials were observer-blinded and collectively included subjects aged 18–70 years. Immunogenicity analysis based on antibody against hepatitis B surface antigen (anti-HBs) levels were based on the per-protocol analysis. Presented here are reverse cumulative frequency plots of anti-HBs serum concentrations for the 3 trials.

Results

Across the trials, reverse cumulative frequency plots of anti-HBs concentrations showed a higher proportion (>90%) of HEPLISAV-B subjects developed a seroprotective antibody level (anti-HBs levels ≥10 mIU/mL) compared with Engerix-B subjects (80% to ~90%). A higher proportion of HEPLISAV-B subjects had anti-HBs levels between 10 mIU/mL and 1,000 mIU/mL. While a higher proportion of Engerix-B subjects had anti-HBs levels >1,000 mIU/mL, a significantly higher proportion of Engerix-B subjects did not develop seroprotective antibody levels. The response curves indicate a more consistent immune response with a higher percentage of subjects achieving seroprotection with less variability for HEPLISAV-B compared with Engerix-B, which showed a more variable response and fewer subjects achieving seroprotection.

Conclusion

HEPLISAV-B, using a CpG adjuvant, results in a higher percentage of persons achieving seroprotection and produces a more uniform and consistent induction of protective antibody levels than Engerix-B, an alum-adjuvanted vaccine.

Disclosures

R. N. Hyer, Dynavax Technologies Corporation: Employee and Shareholder, Salary and Stock options. R. Janssen, Dynavax Technologies Corporation: Employee and Shareholder, Salary and Stock options.

NCRP Program Area Committee 7: Radiation Education, Risk Communication, Outreach, and Policy

In 2013, the National Council on Radiation Protection and Measurements (NCRP) established Program Area Committee 7 (PAC 7) to develop projects and provide guidance on "Radiation Education, Risk Communication, Outreach, and Policy." In 2017, the Committee transitioned to new leadership, the membership was updated, and the purpose, goals, and near-term objectives for PAC 7 were reviewed. Building on the foundation created when the PAC was founded, three near-term action items were identified: (1) to include an NCRP communication strategy and checklist for each report, (2) to apply this strategy to an existing report and the imminent Council Committee 1 report on Radiation Protection in the United States, and (3) to conduct an evaluation and user-friendly cataloging of guides for communicating radiation risk. Other potential products and activities, including some previously identified efforts, were also discussed. Finally, the liaison role with other NCRP committees was further developed with specific identification of a liaison on each of the other PACs to help better incorporate communication, education, outreach, and policy into NCRP activities.

Department of Defense Global Emerging Infections Surveillance and Response System Indian Ocean tsunami response

The Department of Defense (DoD) Global Emerging Infections Surveillance and Response System (DoD-GEIS) identifies and addresses DoD vulnerabilities to emerging infections through a global network of partners. Following the Indian Ocean tsunami of December 26, 2004, DoD-GEIS facilitated the DoD medical response and coordination with the Centers for Disease Control and Prevention and the World Health Organization. DoD-GEIS partners in Southeast Asia (U.S. Naval Medical Research Unit 2, Jakarta, Indonesia; and Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand) rapidly conducted health assessments and established surveillance for communicable diseases that threatened survivors. Preexisting collaboration with the Centers for Disease Control and Prevention, the World Health Organization, and host countries was critical for the DoD-GEIS tsunami response.

Cost-effectiveness analysis of reacquiring and using adenovirus types 4 and 7 vaccines in naval recruits

Adenovirus vaccines have controlled acute respiratory disease (ARD) in military recruits since 1971. Vaccine production, however, ceased and new facilities are required. We assessed whether reacquiring and using vaccines in naval recruits is cost-effective. Three policy options were evaluated: no vaccination, seasonal vaccination, and year-round vaccination. Morbidity (outpatient and inpatient), illness costs (medical and lost training), and vaccine program costs (start-up, acquisition, and distribution) were modeled using a decision-analytic method. Results were based on a cohort of 49,079 annual trainees, a winter vaccine-preventable ARD rate of 2.6 cases per 100 person-weeks, a summer incidence rate at 10% of the winter rate, a hospitalization rate of 7.6%, and a production facility costing US$12 million. Compared to no vaccination, seasonal vaccination prevented 4,015 cases and saved $2.8 million per year. Year-round vaccination prevented 4,555 cases and saved $2.6 million. Reacquiring and using adenovirus vaccines seasonally or year-round saves money and averts suffering.

Telemedical experiences at an Antarctic station

Wintering-over in Antarctica represents a physician's most remote and inaccessible scenario, apart from a space station. Because of the harsh and unpredictable winter weather, Antarctic stations are typically inaccessible for over six months of the year. Telephone and fax communication, and recently other forms of telemedicine, have provided vital links to specialists. The author was the sole physician for more than 250 people wintering-over during the 1995 austral winter at McMurdo Station. There were several instances of serious or life-threatening illness where the author relied on teleconsultation. These cases included new-onset coronary artery disease, posterior hip dislocation, complicated Colles' fracture and acute appendicitis. There were also numerous consultations for non-emergency clinical presentations normally managed by specialists. Telemedicine was a crucial link to specialists from the remote and inaccessible environment of Antarctica.

Insulin-IGF2 region on chromosome 11p encodes a gene implicated in HLA-DR4-dependent diabetes susceptibility

A class of alleles at the VNTR (variable number of tandem repeat) locus in the 5' region of the insulin gene (INS) on chromosome 11p is associated with increased risk of insulin-dependent diabetes mellitus (IDDM), but family studies have failed to demonstrate linkage. INS is thought to contribute to IDDM susceptibility but this view has been difficult to reconcile with the lack of linkage evidence. We thus investigated polymorphisms of INS and neighbouring loci in random diabetics, IDDM multiplex families and controls. HLA-DR4-positive diabetics showed an increased risk associated with common variants at polymorphic sites in a 19-kilobase segment spanned by the 5' INS VNTR and the third intron of the gene for insulin-like growth factor II (IGF2). As INS is the major candidate gene from this region, diabetic and control sequence were compared to identify all INS polymorphisms that could contribute to disease susceptibility. In multiplex families the IDDM-associated alleles were transmitted preferentially to HLA-DR4-positive diabetic offspring from heterozygous parents. The effect was strongest in paternal meioses, suggesting a possible role for maternal imprinting. Our results strongly support the existence of a gene or genes affecting HLA-DR4 IDDM susceptibility which is located in a 19-kilobase region of INS-IGF2. Our results also suggest new ways to map susceptibility loci in other common diseases.