The Role of Booster Vaccination and Ongoing Viral Evolution In Seasonal Circulation of SARS-CoV-2

Periodic resurgences of COVID-19 in the coming years can be expected, while public health interventions may be able to reduce their intensity. We used a transmission model to assess how the use of booster doses and non-pharmaceutical interventions (NPIs) amid ongoing pathogen evolution might influence future transmission waves. We find that incidence is likely to increase as NPIs relax, with a second seasonally driven surge expected in autumn 2022. However, booster doses can greatly reduce the intensity of both waves and reduce cumulative deaths by 20% between 7 January 2022 and 7 January 2023. Reintroducing NPIs during the autumn as incidence begins to increase again could also be impactful. Combining boosters and NPIs results in a 30% decrease in cumulative deaths, with potential for greater impacts if variant-adapted boosters are used. Reintroducing these NPIs in autumn 2022 as transmission rates increase provides similar benefits to sustaining NPIs indefinitely (307 000 deaths with indefinite NPIs and boosters compared with 304 000 deaths with transient NPIs and boosters). If novel variants with increased transmissibility or immune escape emerge, deaths will be higher, but vaccination and NPIs are expected to remain effective tools to decrease both cumulative and peak health system burden, providing proportionally similar relative impacts

Comparative effectiveness of alternative intervals between first and second doses of the mRNA COVID-19 vaccines

The optimal interval between the first and second doses of COVID-19 mRNA vaccines has not been thoroughly evaluated. Employing a target trial emulation approach, we compared the effectiveness of different interdose intervals among >6 million mRNA vaccine recipients in Georgia, USA, from December 2020 to March 2022. We compared three protocols defined by interdose interval: recommended by the Food and Drug Administration (FDA) (17-25 days for Pfizer-BioNTech; 24-32 days for Moderna), late-but-allowable (26-42 days for Pfizer-BioNTech; 33-49 days for Moderna), and late ( ≥ 43 days for Pfizer-BioNTech; ≥50 days for Moderna). In the short-term, the risk of SARS-CoV-2 infection was lowest under the FDA-recommended protocol. Longer-term, the late-but-allowable protocol resulted in the lowest risk (risk ratio on Day 120 after the first dose administration compared to the FDA-recommended protocol: 0.83 [95% confidence interval: 0.82-0.84]). Here, we showed that delaying the second dose by 1-2 weeks may provide stronger long-term protection

Epidemiology in conflict - A call to arms

10.1186/1742-7622-1-5Emerging Themes in Epidemiology

Burden of norovirus in healthcare facilities and strategies for outbreak control

Norovirus is the most frequently occurring cause of community-acquired acute gastroenteritis in people of all ages. It is also one of the most frequent causes of outbreaks in healthcare settings, affecting both long-term care facilities and acute care hospitals. Whereas norovirus gastroenteritis is typically mild and resolves without medical attention, healthcare-associated infections often affect vulnerable populations, resulting in severe infections and disruption of healthcare services. Globally, most norovirus outbreaks in hospitals and residential care institutions are associated with genogroup II type 4 (GII.4) strains. Recent data demonstrate that excess mortality occurs during outbreak periods in healthcare facilities. Nosocomial outbreaks can result in large economic and societal costs. Current control measures for norovirus are largely based on general infection control principles, and treatment is mainly supportive and non-specific. While neither vaccines nor antiviral agents are currently available, both are being developed with encouraging results

Burden of norovirus in healthcare facilities and strategies for outbreak control

Norovirus is the most frequently occurring cause of community-acquired acute gastroenteritis in people of all ages. It is also one of the most frequent causes of outbreaks in healthcare settings, affecting both long-term care facilities and acute care hospitals. Whereas norovirus gastroenteritis is typically mild and resolves without medical attention, healthcare-associated infections often affect vulnerable populations, resulting in severe infections and disruption of healthcare services. Globally, most norovirus outbreaks in hospitals and residential care institutions are associated with genogroup II type 4 (GII.4) strains. Recent data demonstrate that excess mortality occurs during outbreak periods in healthcare facilities. Nosocomial outbreaks can result in large economic and societal costs. Current control measures for norovirus are largely based on general infection control principles, and treatment is mainly supportive and non-specific. While neither vaccines nor antiviral agents are currently available, both are being developed with encouraging results

The rise and fall of HIV prevalence in Zimbabwe: The social, political and economic context

For more than 10 years Zimbabwe has experienced social, political and economic instability, including the near collapse in 2008 of its health system. Paradoxically, this period has also seen a fall in estimated HIV prevalence, from 25.6% in 1996 to 13.7% in 2009. This article examines this development in a socio-political and historical context. We focus on the complex interplay of migration, mortality, individual behaviour change, and economic patterns in shaping the presumed epidemiological waning of HIV prevalence in Zimbabwe and explore the evolution and management of the country's HIV/AIDS response. Our assessment of the role that the Zimbabwean state has played in this development leads to the conclusion that a decline in HIV prevalence has been as much an artefact of dire social, political and economic conditions as the outcome of deliberate interventions. Lastly, we propose the need to contextualise available epidemiological data through qualitative research into the social aspects of HIV and the everyday lives of individuals affected by it