Effectiveness of two doses of tick-borne encephalitis (TBE) vaccine

Vaccine effectiveness (VE) was consistently high following two doses (94.6–97.4%) and three doses (96.1%) of the tick-borne encephalitis (TBE) vaccine. These data support the public health value of providing two doses of the TBE vaccine to a traveller to an endemic area presenting with insufficient time to complete the full three-dose primary series.

Effectiveness of COVID-19 vaccines against Omicron or Delta infection

Background The incidence of SARS-CoV-2 infection, including among those who have received 2 doses of COVID-19 vaccines, has increased substantially since Omicron was first identified in the province of Ontario, Canada. Methods Applying the test-negative design to linked provincial data, we estimated vaccine effectiveness against infection (irrespective of symptoms or severity) caused by Omicron or Delta between November 22 and December 19, 2021. We included individuals who had received at least 2 COVID-19 vaccine doses (with at least 1 mRNA vaccine dose for the primary series) and used multivariable logistic regression to estimate the effectiveness of two or three doses by time since the latest dose. Results We included 3,442 Omicron-positive cases, 9,201 Delta-positive cases, and 471,545 test-negative controls. After 2 doses of COVID-19 vaccine, vaccine effectiveness against Delta infection declined steadily over time but recovered to 93% (95%CI, 92-94%) ≥7 days after receiving an mRNA vaccine for the third dose. In contrast, receipt of 2 doses of COVID-19 vaccines was not protective against Omicron. Vaccine effectiveness against Omicron was 37% (95%CI, 19-50%) ≥7 days after receiving an mRNA vaccine for the third dose. Conclusions Two doses of COVID-19 vaccines are unlikely to protect against infection by Omicron. A third dose provides some protection in the immediate term, but substantially less than against Delta. Our results may be confounded by behaviours that we were unable to account for in our analyses. Further research is needed to examine protection against severe outcomes.

Humoral Immunogenicity of Three COVID-19 mRNA Vaccine Doses in Patients with Inflammatory Bowel Disease

Summary: Herein, we evaluated the humoral immunogenicity of a third COVID-19 mRNA vaccine dose in patients with IBD. All patients were seropositive and had higher antibody concentrations after the third dose than after completion of the two-dose primary series.

Change in COVID-19 risk over time following vaccination with CoronaVac: A test-negative case-control study

Objective To estimate the change in odds of covid-19 over time following primary series completion of the inactivated whole virus vaccine, CoronaVac (Sinovac Biotech) in São Paulo State, Brazil. Design Test negative case-control study. Setting Community testing for covid-19 in São Paulo state, Brazil. Participants Adults aged 18-120 years who were residents of São Paulo state, without a previous laboratory-confirmed covid-19 infection, who received two doses of CoronaVac, and underwent reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 from 17 January to 30 September 2021. Main outcome measures RT-PCR-confirmed symptomatic covid-19 and associated hospital admissions and deaths. Cases were pair-matched to test-negative controls by age (in 5-year bands), municipality of residence, healthcare worker (HCW) status, and date of RT-PCR test (±3 days). Conditional logistic regression was adjusted for sex, number of covid-19-associated comorbidities, race, and previous acute respiratory infection. Results From 137,820 eligible individuals, 37,929 cases with symptomatic covid-19 and 25,756 test-negative controls with covid-19 symptoms were formed into 37,929 matched pairs. Adjusted odds ratios of symptomatic covid-19 increased with time since series completion, and this increase was greater in younger individuals, and among HCWs compared to non-HCWs. Adjusted odds ratios of covid-19 hospitalisation or death were significantly increased from 98 days since series completion, compared to individuals vaccinated 14-41 days previously: 1.40 (95% confidence interval 1.09 to 1.79) from 98-125 days, 1.55 (1.16 to 2.07) from 126-153 days, 1.56 (1.12 to 2.18) from 154-181 days, and 2.12 (1.39-3.22) from 182 days. Conclusions In the general population of São Paulo state, Brazil, an increase in odds of moderate and severe covid-19 outcomes was observed over time following primary series completion with CoronaVac.

A cross-sectional study evaluating tick-borne encephalitis vaccine uptake and timeliness among adults in Switzerland

The goal of this study was to evaluate timeliness of Tick-borne Encephalitis vaccination uptake among adults in Switzerland. In this cross-sectional survey, we collected vaccination records from randomly selected adults 18–79 throughout Switzerland. Of 4,626 participants, data from individuals receiving at least 1 TBE vaccination (n = 1875) were evaluated. We determined year and age of first vaccination and vaccine compliance, evaluating dose timeliness. Participants were considered “on time” if they received doses according to the recommended schedule ± a 15% tolerance period. 45% of participants received their first TBE vaccination between 2006 and 2009, which corresponds to a 2006 change in the official recommendation for TBE vaccination in Switzerland. 25% were first vaccinated aged 50+ (mean age 37). More than 95% of individuals receiving the first dose also received the second; ~85% of those receiving the second dose received the third. For individuals completing the primary series, 30% received 3 doses of Encepur, 58% received 3 doses of FSME-Immun, and 12% received a combination. According to “conventional” schedules, 88% and 79% of individuals received their second and third doses “on time”, respectively. 20% of individuals receiving Encepur received their third dose “too early”. Of individuals completing primary vaccination, 19% were overdue for a booster. Among the 31% of subjects receiving a booster, mean time to first booster was 7.1 years. We estimate that a quarter of adults in Switzerland were first vaccinated for TBE aged 50+. Approximately 80% of participants receiving at least one vaccine dose completed the primary series. We further estimate that 66% of individuals completing the TBE vaccination primary series did so with a single vaccine type and adhered to the recommended schedule.

Haemophilus Influenzae Type B-Diseases

Haemophilus influenzae is a small Gram negative coccobacillus colonizing the respiratory tract of humans. The bacterium may cause direct local infections like otitis media, as well as severe invasive diseases like meningitis. In the prevaccine era, of the 6 capsular serotypes (a–f), type b caused the majority of invasive disease cases, whereas “nontypeable H. influenzae” (NTHi) and other capsular types predominate today. H. influenzae infections affect mainly children <5 years as well as persons >60 years with underlying diseases like COPD. Diagnosis of Hib disease is performed by classical microbiological culture techniques, antigen detection tests and polymerase chain reaction from blood samples, CSF or puncture samples. If untreated or if treatment is delayed, invasive Hib diseases may result in severe consequences such as hearing loss, chronic seizures, learning disabilities, and even death. Safe and effective polysaccharide-conjugate vaccines have been available for children for almost 30 years, reducing invasive Hib-incidences from about 60 to <1 / 105. Today, largely DTP-based Hib-combinations are used. After the primary series with 2 or 3 doses depending on the product and local recommendations, a booster dose in the second year of life is needed to ensure long-term protection.

The immunogenicity and safety of different COVID-19 booster vaccination following CoronaVac or ChAdOx1 nCoV-19 primary series

The appropriate COVID-19 booster vaccine following inactivated or adenoviral vector COVID-19 vaccination is unclear. We evaluated the safety and immunogenicity of different booster vaccines, inactivated (BBIBP-CorV), chimpanzee adenoviral vector (ChAdOx1), or mRNA (BNT162b2 at full (30 µg), or half (15 µg) dose) in healthy adults who received 2-dose primary series of either inactivated vaccine (CoronaVac) or ChAdOx1 8-12 weeks earlier. Overall, the adverse events for all booster vaccines were mild and moderate. Two weeks post-booster dose, the neutralising antibody titres against Delta variant in CoronaVac-prime and ChAdOx1-prime were highest with for 30µg-BNT162b2 (411 vs 470) and 15µg-BNT162b2 (499 vs 358); followed by ChAdOx1 (271 vs 69), and BBIBP-CorV (61.3 vs 49). BNT162b2 also induced higher interferon gamma response. Heterologous COVID-19 boosting vaccination with BNT162b2 is the most immunogenic following CoronaVac or ChAdOx1 primary series. A lower dose BNT162b2 may be used as booster in settings with limited vaccine supply.

The immunogenicity and safety of different COVID-19 booster vaccination following CoronaVac or ChAdOx1 nCoV-19 primary series

The appropriate COVID-19 booster vaccine following inactivated or adenoviral vector COVID-19 vaccination is unclear. We evaluated the safety and immunogenicity of different booster vaccines, inactivated (BBIBP-CorV), chimpanzee adenoviral vector (ChAdOx1), or mRNA (BNT162b2 at full (30 μg), or half (15 μg) dose) in healthy adults who received 2-dose primary series of either inactivated vaccine (CoronaVac) or ChAdOx1 8-12 weeks earlier. Overall, the adverse events for all booster vaccines were mild and moderate. Two weeks post-booster dose, the neutralising antibody titres against Delta variant in CoronaVac-prime and ChAdOx1-prime were highest with for 30μg-BNT162b2 (411 vs 470) and 15μg-BNT162b2 (499 vs 358); followed by ChAdOx1 (271 vs 69), and BBIBP-CorV (61.3 vs 49). BNT162b2 also induced higher interferon gamma response. Heterologous COVID-19 boosting vaccination with BNT162b2 is the most immunogenic following CoronaVac or ChAdOx1 primary series. A lower dose BNT162b2 may be used as booster in settings with limited vaccine supply.

Effectiveness of a third dose of BNT162b2 or mRNA-1273 vaccine for preventing post-vaccination COVID-19 infection: an observational study

Background BNT162b2 and mRNA-1273 vaccines are highly protective against COVID-19. Concern about waning immunity and reduced effectiveness against SARS-COV-2 variants led to use of a third dose six months after completing the primary series. We used data from the Veterans Health Administration to evaluate the effectiveness of a third dose of BNT162b2 or mRNA-1273 compared to the primary series in preventing post-vaccination COVID-19. Methods During January 1 - November 22, 2020, third dose recipients were matched (1:1) to demographically similar controls who did not receive a third dose. Eligible participants had completed the primary series at least six months (180 days) before recruitment date. Long-term care residents were excluded. Primary outcomes were documented SARS-CoV-2 infection and COVID-19 hospitalization. Effectiveness was estimated as 1-incidence rate ratio. Findings Following matching, the BNT162b2 group included 99,856 pairs and the mRNA-1273 group included 74,116 pairs. In BNT162b2 and mRNA-1273 groups, median age was 72 (interquartile range [IQR]: 65-75) and 72 (IQR: 67-76) years, 94,990 (95.1%) and 71,213 (96.1%) were male, and 61,261 (61.3%) and 52,170 (70.4%) were non-Hispanic White, respectively. Effectiveness of a third dose of BNT162b2 or mRNA-1273 compared to the primary series was 49.4% (95% confidence interval [CI]: 41.2-56.5%) and 46.0% (95% CI: 33.5-56.2%) for documented SARS-CoV-2 infection and 52.3% (95% CI: 33.8-65.6%) and 44.7% (95% CI: 10.7-65.7%) for COVID-19 hospitalization, respectively. Interpretation A third dose of BNT162b2 or mRNA-1273 is moderately effective against post-vaccination COVID-19 infection compared to the primary series.