Seasonal trends in COVID-19 cases, hospitalizations, and mortality in the United States and Europe

Will COVID-19 become mild, like a cold?

Several recent studies conclude that an increase in the pathogenicity of SARS-CoV-2 cannot be ruled out. However, it should be noted that SARS-CoV-2 is a 'direct' respiratory virus - meaning it is usually spread by the respiratory route but does not routinely pass through the lymphatics like measles and smallpox. Providing its tropism does not change, it will be unique if its pathogenicity does not decrease until it becomes similar to common cold viruses. Ewald noted in the 1980s that respiratory viruses may evolve mildness because their spread benefits from the mobility of their hosts. This review examines factors that usually lower respiratory viruses' severity, including heat sensitivity (which limits replication in the warmer lungs) and changes to the virus's surface proteins. Other factors may, however, increase pathogenicity, such as replication in the lymphatic system and spreading via solid surfaces or faecal matter. Furthermore, human activities and political events could increase the harmfulness of SARS-CoV-2, including the following: large-scale testing, especially when the results are delayed; transmission in settings where people are close together and not free to move around; poor hygiene facilities; and social, political, or cultural influences that encourage sick individuals to remain active, including crises such as wars. If we can avoid these eventualities, SARS-CoV-2 is likely to evolve to be milder, although the timescale is uncertain. Observations of influenza-like pandemics suggest it may take around two decades for COVID-19 to become as mild as seasonal colds.

Co-administration of recombinant BCG and SARS-CoV-2 proteins leads to robust antiviral immunity

SARS-CoV-2 is the causative virus of COVID-19, which has been responsible for millions of deaths worldwide since its discovery. After its emergence, several variants have been identified that challenge the efficacy of the available vaccines. Previously, we generated and evaluated a vaccine based on a recombinant Bacillus Calmette-Guérin (rBCG) expressing the nucleoprotein (N) of SARS-CoV-2 (rBCG-N-SARS-CoV-2). This protein is a highly immunogenic antigen and well conserved among variants. Here, we tested the administration of this vaccine with recombinant N and viral Spike proteins (S), or Receptor Binding Domain (RBD-Omicron variant), plus a booster with the recombinant proteins only, as a novel and effective strategy to protect against SARS-CoV-2 variants.

METHODS

BALB/c mice were immunized with rBCG-N-SARS-CoV-2 and recombinant SARS-CoV-2 proteins in Alum adjuvant, followed by a booster with recombinant proteins to assess the safety and virus-specific cellular and humoral immune responses against SARS-CoV-2 antigens.

RESULTS

Immunization with rBCG-N-SARS-CoV-2 + recombinant proteins as a vaccine was safe and promoted the activation of CD4+ and CD8+ T cells that recognize SARS-CoV-2 N, S, and RBD antigens. These cells were able to secrete cytokines with an antiviral profile. This immunization strategy also induced robust titers of specific antibodies against N, S, and RBD and neutralizing antibodies of SARS-CoV-2.

CONCLUSIONS

Co-administration of the rBCG-N-SARS-CoV-2 vaccine with recombinant SARS-CoV-2 proteins could be an effective alternative to control particular SARS-CoV-2 variants. Due to its safety and capacity to induce virus-specific immune responses, we believe the rBCG-N-SARS-CoV-2 + Proteins vaccine could be an attractive candidate to protect against this virus, especially in newborns.

Trends in hospitalisations for lower respiratory infections after the COVID-19 pandemic in France

OBJECTIVES

We aimed to evaluate the impact of the pandemic and post-pandemic periods on hospital admissions for LRTI, with a focus on patients with chronic respiratory disease (CRD).

METHODS

From July 2013 to June 2023, monthly numbers of adult hospitalisations for LRTI (excluding SARS-CoV-2) were extracted from the French National Hospital Discharge Database. They were modelled by regressions with autocorrelated errors. Three periods were defined: (1) early pandemic and successive lockdowns; (2) gradual lifting of restrictions and widespread SARS-CoV-2 vaccination; (3) withdrawal of restriction measures.

RESULTS

Pre-pandemic incidence was 96 (90.5 to 101.5) per 100,000 population. Compared with the pre-pandemic period, no more seasonality and significant reductions were estimated in the first two periods: -43.64% (-50.11 to -37.17) and -32.97% (-39.88 to -26.05), respectively. A rebound with a positive trend and a seasonal pattern was observed in period 3. Similar results were observed for CRD patients with no significant difference with pre-pandemic levels in the last period (-9.21%; -20.9% to 1.67%), albeit with differential changes according to the type of CRD.

CONCLUSIONS

COVID-19 pandemic containment measures contributed to changes in LRTI incidence, with a rapid increase and return to a seasonal pattern after their lifting, particularly in patients with CRD.

Variant-specific neutralising antibodies levels induced by the PHH-1 V SARS-CoV-2 vaccine (Bimervax®) by HIPRA

SARS-CoV-2 virus variants continue to emerge at an alarming rate due to spontaneous genetic mutations, particularly in the spike protein receptor-binding domain (RBD) portion, which render the virus more likely to escape immunity. So far, the immunity obtained through global primary and/or booster immunisation campaigns has been sufficient to protect the population from new emerging variants of the Omicron lineage. The current approach to update vaccines' antigen composition to new variants to boost immunity may not be sustainable in the long term. It might also be potentially redundant if the mutations are giving rise to variants which induce milder infections and existing vaccines, such as Bimervax®, are still sufficiently protective, as Covid is slowly becoming a seasonal illness. Through measuring neutralising antibody titres in sera from subjects boosted with Bimervax®, we have demonstrated the ability of Bimervax® to induce immune responses against a variety of SARS-CoV-2 variants, ranging from earlier variants inducing more serious infections to more recent variants which have been found to produce milder infections.

Informing the Need for a SARS-CoV-2 Booster Based on the Immune Responses Among Young Healthy Adults to Variants Circulating in Late 2023

BACKGROUND

COVID-19 remains a global public health challenge due to new immune-evasive SARS-CoV-2 variants and heterogeneous immunity.

METHODS

In this cross-sectional study, we evaluated the adaptive immune responses in US active duty personnel who completed a COVID-19 primary vaccine series and had heterogenous SARS-CoV-2 vaccination and infection histories to 3 previously dominant variants (ancestral, Delta, BA.5) and 3 circulating variants (XBB.1.5, EG.5, and BA.2.86) in late 2023. Analyses were based on the most recent exposure in terms of timing (within or beyond 12 months) and type (vaccine or infection).

RESULTS

Significant reduction was observed in binding antibodies, neutralization antibodies, memory B cells, and CD8+ T cells against circulating variants when compared with previous variants. The reduction in antibody response was more pronounced in those whose most recent exposure was >12 months from enrollment. In contrast, the CD4+ T-cell response was largely consistent across all tested variants. The type of most recent exposure was not a significant factor in determining the magnitude of current immune responses.

CONCLUSIONS

Administration of the XBB.1.5-based booster is likely to enhance cross-reactive humoral responses against SARS-CoV-2 circulating lineages. Ongoing surveillance of immune responses to emerging variants is needed for informing vaccine composition and timing.

A Brighton Collaboration standardized template with key considerations for a benefit-risk assessment for the Comirnaty COVID-19 mRNA vaccine

The Brighton Collaboration Benefit-Risk Assessment of VAccines by TechnolOgy (BRAVATO) Working Group evaluates the safety and other key features of new platform technology vaccines, including nucleic acid (RNA and DNA) vaccines. This manuscript uses the BRAVATO template to report the key considerations for a benefit-risk assessment of the coronavirus disease 2019 (COVID-19) mRNA-based vaccine BNT162b2 (Comirnaty®, or Pfizer-BioNTech COVID-19 vaccine) including the subsequent Original/Omicron BA.1, Original/Omicron BA.4-5 and Omicron XBB.1.5 variant-adapted vaccines developed by BioNTech and Pfizer to protect against COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Initial Emergency Use Authorizations or conditional Marketing Authorizations for the original BNT162b2 vaccine were granted based upon a favorable benefit-risk assessment taking into account clinical safety, immunogenicity, and efficacy data, which was subsequently reconfirmed for younger age groups, and by real world evidence data. In addition, the favorable benefit-risk assessment was maintained for the bivalent vaccines, developed against newly arising SARS-CoV-2 variants, with accumulating clinical trial data.

A decavalent composite mRNA vaccine against both influenza and COVID-19

The COVID-19 pandemic caused by SARS-CoV-2 has had a persistent and significant impact on global public health for 4 years. Recently, there has been a resurgence of seasonal influenza transmission worldwide. The co-circulation of SARS-CoV-2 and seasonal influenza viruses results in a dual burden on communities. Additionally, the pandemic potential of zoonotic influenza viruses, such as avian Influenza A/H5N1 and A/H7N9, remains a concern. Therefore, a combined vaccine against all these respiratory diseases is in urgent need. mRNA vaccines, with their superior efficacy, speed in development, flexibility, and cost-effectiveness, offer a promising solution for such infectious diseases and potential future pandemics. In this study, we present FLUCOV-10, a novel 10-valent mRNA vaccine created from our proven platform. This vaccine encodes hemagglutinin (HA) proteins from four seasonal influenza viruses and two avian influenza viruses with pandemic potential, as well as spike proteins from four SARS-CoV-2 variants. A two-dose immunization with the FLUCOV-10 elicited robust immune responses in mice, producing IgG antibodies, neutralizing antibodies, and antigen-specific cellular immune responses against all the vaccine-matched viruses of influenza and SARS-CoV-2. Remarkably, the FLUCOV-10 immunization provided complete protection in mouse models against both homologous and heterologous strains of influenza and SARS-CoV-2. These results highlight the potential of FLUCOV-10 as an effective vaccine candidate for the prevention of influenza and COVID-19.IMPORTANCEAmidst the ongoing and emerging respiratory viral threats, particularly the concurrent and sequential spread of SARS-CoV-2 and influenza, our research introduces FLUCOV-10. This novel mRNA-based combination vaccine, designed to counteract both influenza and COVID-19, by incorporating genes for surface glycoproteins from various influenza viruses and SARS-CoV-2 variants. This combination vaccine was highly effective in preclinical trials, generating strong immune responses and ensuring protection against both matching and heterologous strains of influenza viruses and SARS-CoV-2. FLUCOV-10 represents a significant step forward in our ability to address respiratory viral threats, showcasing potential as a singular, adaptable vaccine solution for global health challenges.

Urban Wastewater-Based Surveillance of SARS-CoV-2 Virus: A Two-Year Study Conducted in City of Patras, Greece

Wastewater-based epidemiology, during the COVID-19 pandemic years, has been applied as a complementary approach, worldwide, for tracking SARS-CoV-2 virus into the community and used as an early warning of the prevalence of COVID-19 infection. The present study presents the results of the 2-year surveillance project, in the city of Patras, Greece. The purpose of the study was to monitor SARS-CoV-2 and implement WBE as an early warning method of monitoring Public Health impact. The presence of SARS-CoV-2 was determined and quantified in 310 samples using RT-qPCR assays. For the years 2022 and 2023, 93.5% and 78.7% of samples were found positive, respectively. Comparison of detection methods have been conducted to select the method with the highest recovery of the viral load. A seasonal variation of the virus was recorded, showing a recession in summer months confirming the country's epidemiological data as indicated by positive correlation of wastewater viral load with registered cases of COVID-19 infections during these years (p < 0.05) and moreover sealed with a significant negative correlation observed with Daily Average (p < 0.01) and Daily Maximum Temperature (p < 0.01). More research was carried out to elucidate a possible association of physicochemical characteristics of wastewater with viral load showing positive correlation with Chlorides (p < 0.01) advocating possible increased use of chlorine-based disinfectants and Electrical Conductivity (p < 0.01) indicates that wastewater during periods of increased infections is more heavily loaded with ions from chemical and biological pollutants. No correlation found with rainfall and physicochemical indicators, such as COD, BOD5, Total Phosphorus, Total Nitrogen, and Total Suspended Solids. According to the findings, WBE represents a useful tool in the management of epidemics based on an environmental approach and it can also shed light on the interacting parameters that capture Public Health since any infections that may lead to epidemics lead to a parallel change in the use of pharmaceuticals, antimicrobials, disinfectants, and microbial load in urban wastewater.

Tourism promotion during emergency response to Omicron subvariant outbreak

This study aimed to explore optimal ways to promote all kinds of tourism during the phase of emergency response to the current outbreak of Omicron subvariants. A framework-based systematic literature review was conducted as the primary methodology, supported by the preferred reporting items for systematic reviews and meta-analyses checklist. Four analytical units were allocated to include United Nations agencies, governments, tour businesses, and local communities. Economic interest-based tourism promotion was examined to develop local temperature-based tourism promotion via the same four variables. The study found that the pursuit of economic interests was not a productive solution for tourism promotion any longer due to the matter of local weather. It concluded that the four stakeholders should work to replace economic interest-based tourism promotion with local temperature-based tourism promotion. Results of this study can guide the positive effects of warm temperatures, brand image, psychological impacts, digital marketing, and others.

A dynamic ensemble model for short-term forecasting in pandemic situations

During the COVID-19 pandemic, many hospitals reached their capacity limits and could no longer guarantee treatment of all patients. At the same time, governments endeavored to take sensible measures to stop the spread of the virus while at the same time trying to keep the economy afloat. Many models extrapolating confirmed cases and hospitalization rate over short periods of time have been proposed, including several ones coming from the field of machine learning. However, the highly dynamic nature of the pandemic with rapidly introduced interventions and new circulating variants imposed non-trivial challenges for the generalizability of such models. In the context of this paper, we propose the use of ensemble models, which are allowed to change in their composition or weighting of base models over time and could thus better adapt to highly dynamic pandemic or epidemic situations. In that regard, we also explored the use of secondary metadata-Google searches-to inform the ensemble model. We tested our approach using surveillance data from COVID-19, Influenza, and hospital syndromic surveillance of severe acute respiratory infections (SARI). In general, we found ensembles to be more robust than the individual models. Altogether we see our work as a contribution to enhance the preparedness for future pandemic situations.

Assessing the impact of vaccination and medical resource allocation on infectious disease outbreak management: a case study of COVID-19 in Taiyuan City

Introduction

Amidst an emerging infectious disease outbreak, the rational allocation of vaccines and medical resources is crucial for controlling the epidemic's progression.

Method

Analysing COVID-19 data in Taiyuan City from December 2022 to January 2023, this study constructed a S V 1 V 2 V 3 E I Q H R dynamics model to assess the impact of COVID-19 vaccination and resource allocation on epidemic trends.

Results

Vaccination significantly reduces infection rates, hospitalisations, and severe cases, while also curtailing strain on medical resources by reducing congestion periods. An early and sufficient reserve of medical resources can delay the onset of medical congestion, and with increased maximum capacity of medical resources, the congestion's end can be accelerated. Stronger resource allocation capabilities lead to earlier congestion resolution within a fixed total resource pool.

Discussion

Integrating vaccination and medical resource allocation can effectively reduce medical congestion duration and alleviate the epidemic's strain on medical resource capacity (CCMR).

Prioritization of Vaccines for Introduction in the National Immunization Program in the Republic of Korea

This study presents a framework for determining the prioritization of vaccine introduction in the National Immunization Program (NIP) of the Republic of Korea, with a focus on case examples assessed in 2021 and 2023. We describe the predefined criteria for evaluating the prioritization of vaccines in the NIP and the established process in the Republic of Korea. These criteria included disease characteristics, vaccine characteristics, rationality and efficiency of resource allocation, and the acceptance of immunization. The process of prioritizing NIP introduction involved several sequential steps: a demand survey, evidence collection, preliminary evaluation, priority evaluation, and decision making. In 2021 and 2023, 14 and 25 committee members participated in evaluating the prioritization of vaccines in the NIP, respectively. Overall, 13 and 19 NIP vaccine candidates were included in the 2021 and 2023 evaluations, respectively. Through the Delphi survey and consensus processes, the priority order was determined: vaccination against Rotavirus infection was the top priority in 2021, while Influenza 4v (for chronic disease patients) took precedence in 2023. This study demonstrates an evidence-based decision-making process within the healthcare field. The outlined approach may provide valuable guidance for policymakers in other countries seeking to prioritize the inclusion of new vaccines in their NIP.

Proportions and Seasonal Patterns of Respiratory Viruses via Rapid Tests in Adults at a Greek Hospital (Oct. 2023-Mar. 2024)

BACKGROUND

Respiratory infections pose a major public health threat. The predominant viruses causing viral respiratory infections are influenza A and B (Flu-A, Flu-B), coronaviruses, respiratory syncytial virus (RSV), and adenovirus. This study aims to investigate the proportion of these cases via rapid antigen tests and assess seasonal patterns.

METHODS

Clinical samples were collected from symptomatic adults presenting to the Emergency and Respiratory Medicine Departments of the University Hospital of Larissa (UHL), Greece from 16 October 2023 to 31 March 2024. Nasal specimens were antigen-tested for Flu-A/B, SARS-CoV-2, RSV, and adenovirus.

RESULTS

The total sample of specimens collected was 1434, of which 739 (51.5%) were female and 695 were male (48.5%). The mean age of participants was 57 ± 5.5 years. Among the positive results, we recorded a proportion of 40.18% and 11.40% for influenza A and B, respectively, followed by 35.79% for SARS-CoV-2, 10.70% for RSV, and 1.93% for adenovirus.

CONCLUSIONS

In Greece, surveillance systems in infection control are underutilized. Rapid tests via multiple antigens can quickly identify viral infections, making them a valuable tool with financial benefits for health systems. Early detection of respiratory infections helps allocate resources efficiently, ensures adequate staff and facilities are available, and improves patient care through refined clinical management.

Estimated Effectiveness of the BNT162b2 XBB Vaccine Against COVID-19

Importance

Data describing the early additional protection afforded by the recently recommended BNT162b2 XBB vaccine (Pfizer-BioNTech; 2023-2024 formulation) are limited.

Objective

To estimate the association between receipt of the BNT162b2 XBB vaccine and medically attended COVID-19 outcomes among US adults 18 years and older.

Design, Setting, and Participants

This test-negative case-control study was performed to estimate the effectiveness of the BNT162b2 XBB vaccine against COVID-19-associated hospitalization and emergency department (ED) or urgent care (UC) encounters among adults in the Kaiser Permanente Southern California health system between October 10, 2023, and December 10, 2023. Cases were those presenting with an acute respiratory illness and who had a positive SARS-CoV-2 polymerase chain reaction test; controls had an acute respiratory illness but tested negative for SARS-CoV-2.

Exposure

The primary exposure was receipt of the BNT162b2 XBB vaccine compared with not receiving an XBB vaccine of any kind, regardless of prior COVID-19 vaccination or SARS-CoV-2 infection history. Receipt of prior (non-XBB) versions of COVID-19 vaccines was also compared with being unvaccinated to estimate remaining protection from older vaccines.

Main Outcomes and Measures

Analyses for cases and controls were conducted separately for COVID-19 hospital admissions and ED/UC encounters. Adjusted odds ratios and 95% CIs were estimated from multivariable logistic regression models that were adjusted for patient demographic and clinical characteristics. Estimation of vaccine effectiveness was calculated as 1 - odds ratio × 100%.

Results

Among 2854 cases and 15 345 controls (median [IQR] age, 56 [37-72] years; 10 658 [58.6%] female), adjusted estimation of effectiveness of the BNT162b2 XBB vaccine received a median of 34 days prior vs not having received an XBB vaccine of any kind was 62% (95% CI, 32%-79%) against COVID-19 hospitalization and 58% (95% CI, 48%-67%) for ED/UC visits. Compared with being unvaccinated, those who had received only older versions of COVID-19 vaccines did not show statistically significant reduced risk of COVID-19 outcomes, including hospital admission.

Conclusions and Relevance

Findings of this case-control study reaffirm current recommendations for broad age-based use of annually updated COVID-19 vaccines given that (1) the BNT162b2 XBB vaccine provided statistically significant additional protection against a range of COVID-19 outcomes and (2) older versions of COVID-19 vaccines offered little, if any, long-term protection, including against hospital admission, regardless of the number or type of prior doses received.

Evidence base for yearly respiratory virus vaccines: Current status and proposed improved strategies

Annual vaccination is widely recommended for influenza and SARS-CoV-2. In this essay, we analyse and question the prevailing policymaking approach to these respiratory virus vaccines, especially in the United States. Every year, licensed influenza vaccines are reformulated to include specific strains expected to dominate in the season ahead. Updated vaccines are rapidly manufactured and approved without further regulatory requirement of clinical data. Novel vaccines (i.e. new products) typically undergo clinical trials, though generally powered for clinically unimportant outcomes (e.g. lab-confirmed infections, regardless of symptomatology or antibody levels). Eventually, the current and future efficacy of influenza and COVID-19 vaccines against hospitalization or death carries considerable uncertainty. The emergence of highly transmissible SARS-CoV-2 variants and waning vaccine-induced immunity led to plummeting vaccine effectiveness, at least against symptomatic infection, and booster doses have since been widely recommended. No further randomized trials were performed for clinically important outcomes for licensed updated boosters. In both cases, annual vaccine effectiveness estimates are generated by observational research, but observational studies are particularly susceptible to confounding and bias. Well-conducted experimental studies, particularly randomized trials, are necessary to address persistent uncertainties about influenza and COVID-19 vaccines. We propose a new research framework which would render results relevant to the current or future respiratory viral seasons. We demonstrate that experimental studies are feasible by adopting a more pragmatic approach and provide strategies on how to do so. When it comes to implementing policies that seriously impact people's lives, require substantial public resources and/or rely on widespread public acceptance, high evidence standards are desirable.

Incidence of SARS-CoV-2 during the Omicron wave: Results of a longitudinal serosurvey in Québec, Canada

OBJECTIVES

Conventional serological approaches lack sensitivity for the detection of recent SARS-CoV-2 infections in vaccinated individuals, as these individuals exhibit a blunted anti-nucleocapsid (N) response. This limitation was recently addressed by the development of a "ratio-based approach", which compares longitudinally collected specimens. Here, we used this approach to estimate the incidence of SARS-CoV-2 infection and reinfection in Québec (Canada) during the Omicron wave.

METHODS

Consenting plasma donors were included if they donated plasma before December 15, 2021 and during six consecutive periods of ~ 3 months between December 15, 2021 and July 7, 2023 (study period). Anti-N levels were measured with an enzyme-linked immunosorbent assay, and seroconversion was characterized by a ratio of ≥ 1.5 between the optical density of two consecutive samples.

RESULTS

Among the 254 donors, the adjusted proportion of donors (95% confidence interval [CI]) with a new infection ranged between 18.1% (13.2‒23.0) and 24.2% (18.8‒29.7) over Periods 1-5 and fell to 7.9% (4.9‒11.0) during Period 6. During the study period, the proportion of newly infected donors decreased among those aged < 60 (Period 1 = 31.6%, Period 5 = 4.4%), but increased among those aged ≥ 70 (Period 1 = 0.3%, Period 6 = 10.3%). Throughout the study period, 72 (28.3%) reinfections occurred, including two seroconversion events in a single donor. Overall, 87.4% (95% CI = 82.7‒91.2) were infected by SARS-CoV-2 at least once during the study period.

CONCLUSION

The vast majority of the Québec population may have been infected during the Omicron wave. This longitudinal survey demonstrates the usefulness of the "ratio-based approach" for identifying both new infections and reinfections in a vaccinated population.

COVID-19 pandemic in Taiz Governorate, Yemen, between 2020 and 2023

BACKGROUND

The coronavirus disease 2019 (COVID-19) is highly contagious and causes a series of health problems, particularly in Yemen, which has a fragile healthcare system and cannot handle public health emergencies.

AIMS

This analysis aimed to determine the epidemiological status of COVID-19 in the Taiz governorate between April 2020 and December 2023.

METHODS

A retrospective study based on surveillance data from the Taiz governorate was used. The required data were gathered from the Ministry of Health and Population in Aden and analyzed using SPSS.

RESULTS

Out of 5826 suspected of COVID-19 cases, 1933 (33.18%) cases were positive for COVID-19 infection. The high rates of COVID-19 cases were reported at 35.40% in males, 37.80% in people aged 35-44 years, 47.20% in 2020, 72.73% in Dhubab district, and 27.78% in March 2021. The overall incidence rate of cases was reported at 6.2 per 10,000 people in Taiz governorate (8.85 in males and 3.80 in females). In addition, the high incidence rate of COVID-19 was observed among age groups ≥ 65 years, in 2021, and in Al-Mukha districts. In total, the rate of fatality cases was 14.12%, the higher rate of fatality cases was 15.46% among males and 32.23% among individuals aged ≥ 65 years, and 26.97% in 2020.

CONCLUSION

In this finding, the incidence rate of COVID-19 is high. It is necessary to increase the public's awareness of the transmission and prevention methods of COVID-19, as well as implement appropriate strategies to protect populations from infectious diseases.

COVID-19 vaccination: 2023 Taiwan Association of Gerontology and Geriatrics (TAGG) consensus statements

The COVID-19 pandemic remains challenging due to the rapid evolution of the severe acute respiratory syndrome coronavirus 2. This article discusses recent findings on high-risk groups for COVID-19 mortality and morbidity, along with consensus statements from the 2023 Taiwan Association of Gerontology and Geriatrics (TAGG) meeting. It examines evidence on viral mutation mechanisms, emerging variants, and their implications for vaccination strategies. The article underscores advanced age, immunocompromised status, chronic medical conditions, occupational exposure, and socioeconomic disparities as significant risk factors for severe COVID-19 outcomes. TAGG's consensus emphasizes robust vaccination promotion, prioritizing elderly, and immunocompromised groups, individualized multi-dose regimens for immunocompromised patients, and simplified clinical guidelines. Discussions on global and regional recommendations for regular, variant-adapted boosters highlight the non-seasonal nature of COVID-19. Key agreements include escalating domestic preparedness, implementing vigorous risk-based vaccination, and adapting global guidelines to local contexts. Given ongoing viral evolution, proactive adjustment of vaccination policies is essential. Scientific consensus, tailored recommendations, and rapid knowledge dissemination are vital for optimizing COVID-19 protection among vulnerable groups in Taiwan. This article seeks to inform clinical practice and public health policy by summarizing expert-driven vaccination perspectives.

A Paper-Based Multiplexed Serological Test to Monitor Immunity against SARS-COV-2 Using Machine Learning

The rapid spread of SARS-CoV-2 caused the COVID-19 pandemic and accelerated vaccine development to prevent the spread of the virus and control the disease. Given the sustained high infectivity and evolution of SARS-CoV-2, there is an ongoing interest in developing COVID-19 serology tests to monitor population-level immunity. To address this critical need, we designed a paper-based multiplexed vertical flow assay (xVFA) using five structural proteins of SARS-CoV-2, detecting IgG and IgM antibodies to monitor changes in COVID-19 immunity levels. Our platform not only tracked longitudinal immunity levels but also categorized COVID-19 immunity into three groups: protected, unprotected, and infected, based on the levels of IgG and IgM antibodies. We operated two xVFAs in parallel to detect IgG and IgM antibodies using a total of 40 μL of human serum sample in <20 min per test. After the assay, images of the paper-based sensor panel were captured using a mobile phone-based custom-designed optical reader and then processed by a neural network-based serodiagnostic algorithm. The serodiagnostic algorithm was trained with 120 measurements/tests and 30 serum samples from 7 randomly selected individuals and was blindly tested with 31 serum samples from 8 different individuals, collected before vaccination as well as after vaccination or infection, achieving an accuracy of 89.5%. The competitive performance of the xVFA, along with its portability, cost-effectiveness, and rapid operation, makes it a promising computational point-of-care (POC) serology test for monitoring COVID-19 immunity, aiding in timely decisions on the administration of booster vaccines and general public health policies to protect vulnerable populations.

COVID-19 Vaccine Effectiveness in Autumn and Winter 2022 to 2023 Among Older Europeans

Importance

In the context of emerging SARS-CoV-2 variants or lineages and new vaccines, it is key to accurately monitor COVID-19 vaccine effectiveness (CVE) to inform vaccination campaigns.

Objective

To estimate the effectiveness of COVID-19 vaccines administered in autumn and winter 2022 to 2023 against symptomatic SARS-CoV-2 infection (with all circulating viruses and XBB lineage in particular) among people aged 60 years or older in Europe, and to compare different CVE approaches across the exposed and reference groups used.

Design, Setting, and Participants

This case-control study obtained data from VEBIS (Vaccine Effectiveness, Burden and Impact Studies), a multicenter study that collects COVID-19 and influenza data from 11 European sites: Croatia; France; Germany; Hungary; Ireland; Portugal; the Netherlands; Romania; Spain, national; Spain, Navarre region; and Sweden. Participants were primary care patients aged 60 years or older with acute respiratory infection symptoms who were recruited at the 11 sites after the start of the COVID-19 vaccination campaign from September 2022 to August 2023. Cases and controls were defined as patients with positive and negative, respectively, reverse transcription-polymerase chain reaction (RT-PCR) test results.

Exposures

The exposure was COVID-19 vaccination. The exposure group consisted of patients who received a COVID-19 vaccine during the autumn and winter 2022 to 2023 vaccination campaign and 14 days or more before symptom onset. Reference group included patients who were not vaccinated during or in the 6 months before the 2022 to 2023 campaign (seasonal CVE), those who were never vaccinated (absolute CVE), and those who were vaccinated with at least the primary series 6 months or more before the campaign (relative CVE). For relative CVE of second boosters, patients receiving their second booster during the campaign were compared with those receiving 1 booster 6 months or more before the campaign.

Main Outcomes and Measures

The outcome was RT-PCR-confirmed, medically attended, symptomatic SARS-CoV-2 infection. Four CVE estimates were generated: seasonal, absolute, relative, and relative of second boosters. CVE was estimated using logistic regression, adjusting for study site, symptom onset date, age, chronic condition, and sex.

Results

A total of 9308 primary care patients were included, with 1687 cases (1035 females; median [IQR] age, 71 [65-79] years) and 7621 controls (4619 females [61%]; median [IQR] age, 71 [65-78] years). Within 14 to 89 days after vaccination, seasonal CVE was 29% (95% CI, 14%-42%), absolute CVE was 39% (95% CI, 6%-60%), relative CVE was 31% (95% CI, 15% to 44%), and relative CVE of second boosters was 34% (95% CI, 18%-47%) against all SARS-CoV-2 variants. In the same interval, seasonal CVE was 44% (95% CI, -10% to 75%), absolute CVE was 52% (95% CI, -23% to 82%), relative CVE was 47% (95% CI, -8% to 77%), and relative CVE of second boosters was 46% (95% CI, -13% to 77%) during a period of high XBB circulation. Estimates decreased with time since vaccination, with no protection from 180 days after vaccination.

Conclusions and Relevance

In this case-control study among older Europeans, all CVE approaches suggested that COVID-19 vaccines administered in autumn and winter 2022 to 2023 offered at least 3 months of protection against symptomatic, medically attended, laboratory-confirmed SARS-CoV-2 infection. The effectiveness of new COVID-19 vaccines against emerging SARS-CoV-2 variants should be continually monitored using CVE seasonal approaches.

Updated Surveillance Metrics and History of the COVID-19 Pandemic (2020-2023) in Europe: Longitudinal Trend Analysis

BACKGROUND

In this study, we built upon our initial research published in 2020 by incorporating an additional 2 years of data for Europe. We assessed whether COVID-19 had shifted from the pandemic to endemic phase in the region when the World Health Organization (WHO) declared the end of the public health emergency of international concern on May 5, 2023.

OBJECTIVE

We first aimed to measure whether there was an expansion or contraction in the pandemic in Europe at the time of the WHO declaration. Second, we used dynamic and genomic surveillance methods to describe the history of the pandemic in the region and situate the window of the WHO declaration within the broader history. Third, we provided the historical context for the course of the pandemic in Europe in terms of policy and disease burden at the country and region levels.

METHODS

In addition to the updates of traditional surveillance data and dynamic panel estimates from the original study, this study used data on sequenced SARS-CoV-2 variants from the Global Initiative on Sharing All Influenza Data to identify the appearance and duration of variants of concern. We used Nextclade nomenclature to collect clade designations from sequences and Pangolin nomenclature for lineage designations of SARS-CoV-2. Finally, we conducted a 1-tailed t test for whether regional weekly speed was greater than an outbreak threshold of 10. We ran the test iteratively with 6 months of data across the sample period.

RESULTS

Speed for the region had remained below the outbreak threshold for 4 months by the time of the WHO declaration. Acceleration and jerk were also low and stable. While the 1-day and 7-day persistence coefficients remained statistically significant, the coefficients were moderate in magnitude (0.404 and 0.547, respectively; P<.001 for both). The shift parameters for the 2 weeks around the WHO declaration were small and insignificant, suggesting little change in the clustering effect of cases on future cases at the time. From December 2021 onward, Omicron was the predominant variant of concern in sequenced viral samples. The rolling t test of speed equal to 10 became insignificant for the first time in April 2023.

CONCLUSIONS

While COVID-19 continues to circulate in Europe, the rate of transmission remained below the threshold of an outbreak for 4 months ahead of the WHO declaration. The region had previously been in a nearly continuous state of outbreak. The more recent trend suggested that COVID-19 was endemic in the region and no longer reached the threshold of the pandemic definition. However, several countries remained in a state of outbreak, and the conclusion that COVID-19 was no longer a pandemic in Europe at the time is unclear.

Does behavior mediate the effect of weather on SARS-CoV-2 transmission? evidence from cell-phone data

There is growing evidence that weather alters SARS-CoV-2 transmission, but it remains unclear what drives the phenomenon. One prevailing hypothesis is that people spend more time indoors in cooler weather, leading to increased spread of SARS-CoV-2 related to time spent in confined spaces and close contact with others. However, the evidence in support of that hypothesis is limited and, at times, conflicting. We use a mediation framework, and combine daily weather, COVID-19 hospital surveillance, cellphone-based mobility data and building footprints to estimate the relationship between daily indoor and outdoor weather conditions, mobility, and COVID-19 hospitalizations. We quantify the direct health impacts of weather on COVID-19 hospitalizations and the indirect effects of weather via time spent indoors away-from-home on COVID-19 hospitalizations within five Colorado counties between March 4th 2020 and January 31st 2021. We also evaluated the evidence for seasonal effect modification by comparing the results of all-season (using season as a covariate) to season-stratified models. Four weather conditions were associated with both time spent indoors away-from-home and 12-day lagged COVID-19 hospital admissions in one or more season: high minimum temperature (all-season), low maximum temperature (spring), low minimum absolute humidity (winter), and high solar radiation (all-season & winter). In our mediation analyses, we found evidence that changes in 12-day lagged hospital admissions were primarily via the direct effects of weather conditions, rather than via indirect effects by which weather changes time spent indoors away-from-home. Our findings do not support the hypothesis that weather impacted SARS-CoV-2 transmission via changes in mobility patterns during the first year of the pandemic. Rather, weather appears to have impacted SARS-CoV-2 transmission primarily via mechanisms other than human movement. We recommend further analysis of this phenomenon to determine whether these findings generalize to current SARS-CoV-2 transmission dynamics, as well as other seasonal respiratory pathogens.

Strengthening Pediatric and Public Health Collaboration to Protect Children's Health During a Pandemic

This article examines lessons learned from previous pandemics, including the 2009 H1N1 influenza and the coronavirus disease 2019 pandemic. Pediatric providers have a unique and important role and strategies to improve collaboration and communication between public health and pediatric providers are essential during public health emergencies. A robust network of communication channels, effective public health messaging, and pediatric-focused disease related, and program outcome data are key to supporting a coordinated response to future pandemics. Critical issues include real-time communication with and engagement of pediatric providers as well as optimizing best evidence approaches for pediatric care while considering the distinct challenges facing children and their families.

COVID-19 Vaccination Strategies in the Endemic Period: Lessons from Influenza

Coronavirus disease 2019 (COVID-19) is a highly contagious zoonotic respiratory disease with many similarities to influenza. Effective vaccines are available for both; however, rapid viral evolution and waning immunity make them virtually impossible to eradicate with vaccines. Thus, the practical goal of vaccination is to reduce the incidence of serious illnesses and death. Three years after the introduction of COVID-19 vaccines, the optimal vaccination strategy in the endemic period remains elusive, and health authorities worldwide have begun to adopt various approaches. Herein, we propose a COVID-19 vaccination strategy based on the data available until early 2024 and discuss aspects that require further clarification for better decision making. Drawing from comparisons between COVID-19 and influenza vaccination strategies, our proposed COVID-19 vaccination strategy prioritizes high-risk groups, emphasizes seasonal administration aligned with influenza vaccination campaigns, and advocates the co-administration with influenza vaccines to increase coverage.

Evaluation of Strategies for Transitioning to Annual SARS-CoV-2 Vaccination Campaigns in the United States

BACKGROUND

The U.S. Food and Drug Administration has proposed administering annual SARS-CoV-2 vaccines.

OBJECTIVE

To evaluate the effectiveness of an annual SARS-CoV-2 vaccination campaign, quantify the health and economic benefits of a second dose provided to children younger than 2 years and adults aged 50 years or older, and optimize the timing of a second dose.

DESIGN

An age-structured dynamic transmission model.

SETTING

United States.

PARTICIPANTS

A synthetic population reflecting demographics and contact patterns in the United States.

INTERVENTION

Vaccination against SARS-CoV-2 with age-specific uptake similar to that of influenza vaccination.

MEASUREMENTS

Incidence, hospitalizations, deaths, and direct health care cost.

RESULTS

The optimal timing between the first and second dose delivered to children younger than 2 years and adults aged 50 years or older in an annual vaccination campaign was estimated to be 5 months. In direct comparison with a single-dose campaign, a second booster dose results in 123 869 fewer hospitalizations (95% uncertainty interval [UI], 121 994 to 125 742 fewer hospitalizations) and 5524 fewer deaths (95% UI, 5434 to 5613 fewer deaths), averting $3.63 billion (95% UI, $3.57 billion to $3.69 billion) in costs over a single year.

LIMITATIONS

Population immunity is subject to degrees of immune evasion for emerging SARS-CoV-2 variants. The model was implemented in the absence of nonpharmaceutical interventions and preexisting vaccine-acquired immunity.

CONCLUSION

The direct health care costs of SARS-CoV-2, particularly among adults aged 50 years or older, would be substantially reduced by administering a second dose 5 months after the initial dose.

PRIMARY FUNDING SOURCE

Natural Sciences and Engineering Research Council of Canada, Notsew Orm Sands Foundation, National Institutes of Health, Centers for Disease Control and Prevention, and National Science Foundation.

Severity of Omicron Subvariants and Vaccine Impact in Catalonia, Spain

In the current COVID-19 landscape dominated by Omicron subvariants, understanding the timing and efficacy of vaccination against emergent lineages is crucial for planning future vaccination campaigns, yet detailed studies stratified by subvariant, vaccination timing, and age groups are scarce. This retrospective study analyzed COVID-19 cases from December 2021 to January 2023 in Catalonia, Spain, focusing on vulnerable populations affected by variants BA.1, BA.2, BA.5, and BQ.1 and including two national booster campaigns. Our database includes detailed information such as dates of diagnosis, hospitalization and death, last vaccination, and cause of death, among others. We evaluated the impact of vaccination on disease severity by age, variant, and vaccination status, finding that recent vaccination significantly mitigated severity across all Omicron subvariants, although efficacy waned six months post-vaccination, except for BQ.1, which showed more stable levels. Unvaccinated individuals had higher hospitalization and mortality rates. Our results highlight the importance of periodic vaccination to reduce severe outcomes, which are influenced by variant and vaccination timing. Although the seasonality of COVID-19 is uncertain, our analysis suggests the potential benefit of annual vaccination in populations >60 years old, probably in early fall, if COVID-19 eventually exhibits a major peak similar to other respiratory viruses.

Comparison of SARS-CoV-2 variants of concern in primary human nasal cultures demonstrates Delta as most cytopathic and Omicron as fastest replicating

The SARS-CoV-2 pandemic was marked with emerging viral variants, some of which were designated as variants of concern (VOCs) due to selection and rapid circulation in the human population. Here, we elucidate functional features of each VOC linked to variations in replication rate. Patient-derived primary nasal cultures grown at air-liquid interface were used to model upper respiratory infection and compared to cell lines derived from human lung epithelia. All VOCs replicated to higher titers than the ancestral virus, suggesting a selection for replication efficiency. In primary nasal cultures, Omicron replicated to the highest titers at early time points, followed by Delta, paralleling comparative studies of population sampling. All SARS-CoV-2 viruses entered the cell primarily via a transmembrane serine protease 2 (TMPRSS2)-dependent pathway, and Omicron was more likely to use an endosomal route of entry. All VOCs activated and overcame dsRNA-induced cellular responses, including interferon (IFN) signaling, oligoadenylate ribonuclease L degradation, and protein kinase R activation. Among the VOCs, Omicron infection induced expression of the most IFN and IFN-stimulated genes. Infections in nasal cultures resulted in cellular damage, including a compromise of cell barrier integrity and loss of nasal cilia and ciliary beating function, especially during Delta infection. Overall, Omicron was optimized for replication in the upper respiratory tract and least favorable in the lower respiratory cell line, and Delta was the most cytopathic for both upper and lower respiratory cells. Our findings highlight the functional differences among VOCs at the cellular level and imply distinct mechanisms of pathogenesis in infected individuals.

IMPORTANCE

Comparative analysis of infections by SARS-CoV-2 ancestral virus and variants of concern, including Alpha, Beta, Delta, and Omicron, indicated that variants were selected for efficiency in replication. In infections of patient-derived primary nasal cultures grown at air-liquid interface to model upper respiratory infection, Omicron reached the highest titers at early time points, a finding that was confirmed by parallel population sampling studies. While all infections overcame dsRNA-mediated host responses, infections with Omicron induced the strongest interferon and interferon-stimulated gene response. In both primary nasal cultures and lower respiratory cell line, infections by Delta were most damaging to the cells as indicated by syncytia formation, loss of cell barrier integrity, and nasal ciliary function.

From pandemic to endemic: Divergence of COVID-19 positive-tests and hospitalization numbers from SARS-CoV-2 RNA levels in wastewater of Rochester, Minnesota

Traditionally, public health surveillance relied on individual-level data but recently wastewater-based epidemiology (WBE) for the detection of infectious diseases including COVID-19 became a valuable tool in the public health arsenal. Here, we use WBE to follow the course of the COVID-19 pandemic in Rochester, Minnesota (population 121,395 at the 2020 census), from February 2021 to December 2022. We monitored the impact of SARS-CoV-2 infections on public health by comparing three sets of data: quantitative measurements of viral RNA in wastewater as an unbiased reporter of virus level in the community, positive results of viral RNA or antigen tests from nasal swabs reflecting community reporting, and hospitalization data. From February 2021 to August 2022 viral RNA levels in wastewater were closely correlated with the oscillating course of COVID-19 case and hospitalization numbers. However, from September 2022 cases remained low and hospitalization numbers dropped, whereas viral RNA levels in wastewater continued to oscillate. The low reported cases may reflect virulence reduction combined with abated inclination to report, and the divergence of virus levels in wastewater from reported cases may reflect COVID-19 shifting from pandemic to endemic. WBE, which also detects asymptomatic infections, can provide an early warning of impending cases, and offers crucial insights during pandemic waves and in the transition to the endemic phase.

Does behavior mediate the effect of weather on SARS-CoV-2 transmission? Evidence from cell-phone data

Background

There is growing evidence that weather alters SARS-CoV-2 transmission, but it remains unclear what drives the phenomenon. One prevailing hypothesis is that people spend more time indoors in cooler weather, leading to increased spread of SARS-CoV-2 related to time spent in confined spaces and close contact with others. However, the evidence in support of that hypothesis is limited and, at times, conflicting.

Objectives

We aim to evaluate the extent to which weather impacts COVID-19 via time spent away-from-home in indoor spaces, as compared to a direct effect of weather on COVID-19 hospitalization, independent of mobility.

Methods

We use a mediation framework, and combine daily weather, COVID-19 hospital surveillance, cellphone-based mobility data and building footprints to estimate the relationship between daily indoor and outdoor weather conditions, mobility, and COVID-19 hospitalizations. We quantify the direct health impacts of weather on COVID-19 hospitalizations and the indirect effects of weather via time spent indoors away-from-home on COVID-19 hospitalizations within five Colorado counties between March 4th 2020 and January 31st 2021.

Results

We found evidence that changes in 12-day lagged hospital admissions were primarily via the direct effects of weather conditions, rather than via indirect effects by which weather changes time spent indoors away-from-home. Sensitivity analyses evaluating time at home as a mediator were consistent with these conclusions.

Discussion

Our findings do not support the hypothesis that weather impacted SARS-CoV-2 transmission via changes in mobility patterns during the first year of the pandemic. Rather, weather appears to have impacted SARS-CoV-2 transmission primarily via mechanisms other than human movement. We recommend further analysis of this phenomenon to determine whether these findings generalize to current SARS-CoV-2 transmission dynamics and other seasonal respiratory pathogens.

An intranasal combination vaccine induces systemic and mucosal immunity against COVID-19 and influenza

Despite prolonged surveillance and interventions, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses continue to pose a severe global health burden. Thus, we developed a chimpanzee adenovirus-based combination vaccine, AdC68-HATRBD, with dual specificity against SARS-CoV-2 and influenza virus. When used as a standalone vaccine, intranasal immunization with AdC68-HATRBD induced comprehensive and potent immune responses consisting of immunoglobin (Ig) G, mucosal IgA, neutralizing antibodies, and memory T cells, which protected the mice from BA.5.2 and pandemic H1N1 infections. When used as a heterologous booster, AdC68-HATRBD markedly improved the protective immune response of the licensed SARS-CoV-2 or influenza vaccine. Therefore, whether administered intranasally as a standalone or booster vaccine, this combination vaccine is a valuable strategy to enhance the overall vaccine efficacy by inducing robust systemic and mucosal immune responses, thereby conferring dual lines of immunological defenses for these two viruses.

Reconciling the efficacy and effectiveness of masking on epidemic outcomes

During the COVID-19 pandemic, mask wearing in public settings has been a key control measure. However, the reported effectiveness of masking has been much lower than laboratory measures of efficacy, leading to doubts on the utility of masking. Here, we develop an agent-based model that comprehensively accounts for individual masking behaviours and infectious disease dynamics, and test the impact of masking on epidemic outcomes. Using realistic inputs of mask efficacy and contact data at the individual level, the model reproduces the lower effectiveness as reported in randomized controlled trials. Model results demonstrate that transmission within households, where masks are rarely used, can substantially lower effectiveness, and reveal the interaction of nonlinear epidemic dynamics, control measures and potential measurement biases. Overall, model results show that, at the individual level, consistent masking can reduce the risk of first infection and, over time, reduce the frequency of repeated infection. At the population level, masking can provide direct protection to mask wearers, as well as indirect protection to non-wearers, collectively reducing epidemic intensity. These findings suggest it is prudent for individuals to use masks during an epidemic, and for policymakers to recognize the less-than-ideal effectiveness of masking when devising public health interventions.

"Every Time It Comes Time for Another Shot, It's a Re-Evaluation": A Qualitative Study of Intent to Receive COVID-19 Boosters among Parents Who Were Hesitant Adopters of the COVID-19 Vaccine

COVID-19 vaccine coverage remains low for US children, especially among those living in rural areas and the Southern/Southeastern US. As of 12 September 2023, the CDC recommended bivalent booster doses for everyone 6 months and older. Emerging research has shown an individual may be vaccine hesitant and also choose to receive a vaccine for themselves or their child(ren); however, little is known regarding how hesitant adopters evaluate COVID-19 booster vaccinations. We used an exploratory qualitative descriptive study design and conducted individual interviews with COVID-19 vaccine-hesitant adopter parents (n = 20) to explore COVID-19 parental intentions to have children receive COVID-19 boosters. Three primary themes emerged during the analysis: risk, confidence, and intent, with risk assessments from COVID-19 and COVID-19 vaccine confidence often related to an individual parent's intent to vaccinate. We also found links among individuals with persistent concerns about the COVID-19 vaccine and low COVID-19 vaccine confidence with conditional and/or low/no intent and refusal to receive recommended boosters for children. Our findings suggest that healthcare providers and public health officials should continue making strong recommendations for vaccines, continue to address parental concerns, and provide strong evidence for vaccine safety and efficacy even among the vaccinated.

Descriptive analysis to assess seasonal patterns of COVID-19 and influenza in low-income and middle-income countries in Asia, the Middle East and Latin America

OBJECTIVES

Understanding disease seasonality can help predict the occurrence of outbreaks and inform public health planning. Respiratory diseases typically follow seasonal patterns; however, knowledge regarding the seasonality of COVID-19 and its impact on the seasonality of influenza remains limited. The objective of this study was to provide more evidence to understand the circulation of SARS-CoV-2, the virus responsible for COVID-19, in an endemic scenario to guide potential preventive strategies.

DESIGN

In this study, a descriptive analysis was undertaken to describe seasonality trends and/or overlap between COVID-19 and influenza in 12 low-income and middle-income countries using Our World in Data and FluMart data sources. Plots of COVID-19 and influenza cases were analysed.

SETTING

Singapore, Thailand, Malaysia, the Philippines, Argentina, Brazil, Mexico, South Africa, Morocco, Bahrain, Qatar and Saudi Arabia.

OUTCOME MEASURES

COVID-19 cases and influenza cases.

RESULTS

No seasonal patterns of SARS-CoV-2 or SARS-CoV-2/influenza cocirculation were observed in most countries, even when considering the avian influenza pandemic period.

CONCLUSIONS

These results can inform public health strategies. The lack of observed seasonal behaviour highlights the importance of maintaining year-round vaccination rather than implementing seasonal campaigns. Further research investigating the influence of climate conditions, social behaviour and year-round preventive measures could be fundamental for shaping appropriate policies related to COVID-19 and respiratory viral disease control in low-income and middle-income countries as COVID-19 variant data and epidemiologic patterns accrue over time.

Influence of Seasonality and Public-Health Interventions on the COVID-19 Pandemic in Northern Europe

BACKGROUND

Most government efforts to control the COVID-19 pandemic revolved around non-pharmaceutical interventions (NPIs) and vaccination. However, many respiratory diseases show distinctive seasonal trends. In this manuscript, we examined the contribution of these three factors to the progression of the COVID-19 pandemic.

METHODS

Pearson correlation coefficients and time-lagged analysis were used to examine the relationship between NPIs, vaccinations and seasonality (using the average incidence of endemic human beta-coronaviruses in Sweden over a 10-year period as a proxy) and the progression of the COVID-19 pandemic as tracked by deaths; cases; hospitalisations; intensive care unit occupancy and testing positivity rates in six Northern European countries (population 99.12 million) using a population-based, observational, ecological study method.

FINDINGS

The waves of the pandemic correlated well with the seasonality of human beta-coronaviruses (HCoV-OC43 and HCoV-HKU1). In contrast, we could not find clear or consistent evidence that the stringency of NPIs or vaccination reduced the progression of the pandemic. However, these results are correlations and not causations.

IMPLICATIONS

We hypothesise that the apparent influence of NPIs and vaccines might instead be an effect of coronavirus seasonality. We suggest that policymakers consider these results when assessing policy options for future pandemics.

LIMITATIONS

The study is limited to six temperate Northern European countries with spatial and temporal variations in metrics used to track the progression of the COVID-19 pandemic. Caution should be exercised when extrapolating these findings.

Responses to Common Misconceptions Relating to COVID-19 Variant-Adapted mRNA Vaccines

The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the waning of immunity over time has necessitated the use of booster doses of original coronavirus disease 2019 (COVID-19) vaccines. This has also led to the development and implementation of variant-adapted messenger RNA (mRNA) vaccines that include an Omicron sub-lineage component in addition to the antigen based on the wild-type virus spike protein. Subsequent emergence of the recombinant XBB sub-lineages triggered the development of monovalent XBB-based variant-adapted mRNA vaccines, which are available for vaccination campaigns in late 2023. Misconceptions about new variant-adapted vaccines may exacerbate vaccine fatigue and drive the lack of vaccine acceptance. This article aims to address common concerns about the development and use of COVID-19 variant-adapted mRNA vaccines that have emerged as SARS-CoV-2 has continued to evolve.

Effectiveness of a fourth dose of COVID-19 mRNA vaccine in patients with systemic autoimmune rheumatic diseases using disease-modifying antirheumatic drugs: an emulated target trial

BACKGROUND

Patients with systemic autoimmune rheumatic diseases using disease-modifying antirheumatic drugs (DMARDs) might have blunted responses to COVID-19 vaccines. The initial mRNA vaccine series is defined as three doses for this population and a fourth booster dose is recommended. The effectiveness of the fourth dose in patients with systemic autoimmune rheumatic diseases using DMARDs is not well established. We aimed to assess the effectiveness of receiving versus not receiving a fourth dose of COVID-19 mRNA vaccine using a target trial framework, in a cohort of patients with systemic autoimmune rheumatic diseases receiving DMARD therapy.

METHODS

We conducted an emulated target trial using observational data from the Mass General Brigham health-care system to compare receiving versus not receiving a fourth mRNA vaccine dose. Analysed patients had systemic autoimmune rheumatic diseases, were prescribed DMARDs, and were eligible for a fourth dose of BNT162b2 or mRNA-1273 vaccines between Jan 16 and June 11, 2022. To account for temporal changes, the study period was divided into 1-week intervals. Fourth-dose-exposed patients were included in a 1-week interval if they received a fourth mRNA dose in that interval; fourth-dose-unexposed patients were eligible for but had not received the fourth dose of the vaccine. The primary outcome was a SARS-CoV-2 infection; the secondary outcome was severe SARS-CoV-2 infection (ie, admission to hospital or death within -3 to +14 days of a positive test). We assessed the effectiveness of the fourth dose using time-stratified, overlap propensity score-weighted Cox regression models.

FINDINGS

We included 4305 patients, 3126 of whom received a fourth dose of vaccine and 1179 who had not. The median follow-up time was 135 days (IQR 112-154) among patients who had received a fourth dose and 65 days (30-156) among patients who had not received a fourth dose. After overlap weighting in both groups, 1863 (72·7%) of 2563 participants were women, 700 (27·3%) were men, and 2242 (87·5%) were White. Rheumatoid arthritis was present in 1392 (54·3%) of 2563 participants; the most frequent treatments were conventional synthetic DMARDs (1489 [58·1%]) or biological DMARDs (1007 [39·3%]). SARS-CoV-2 infection risk was lower among patients receiving versus not receiving a fourth dose of vaccine (HR 0·59 [95% CI 0·47-0·74]). A fourth dose reduced the risk of admission to hospital or death within -3 to +14 days of SARS-CoV-2 infection (0·35 [0·14-0·85]).

INTERPRETATION

In this emulated target trial, a fourth dose of COVID-19 mRNA vaccine reduced the risk of SARS-CoV-2 infection and severe COVID-19 among patients with systemic autoimmune rheumatic diseases using DMARDs during the Omicron era. Patients with systemic autoimmune rheumatic diseases should be encouraged to remain up-to-date with COVID-19 vaccinations.

FUNDING

The National Institutes of Health and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Seasonality of COVID-19 incidence in the United States

Background

The surges of Coronavirus Disease 2019 (COVID-19) appeared to follow a repeating pattern of COVID-19 outbreaks regardless of social distancing, mask mandates, and vaccination campaigns.

Objectives

This study aimed to investigate the seasonality of COVID-19 incidence in the United States of America (USA), and to delineate the dominant frequencies of the periodic patterns of the disease.

Methods

We characterized periodicity in COVID-19 incidences over the first three full seasonal years (March 2020 to March 2023) of the COVID-19 pandemic in the USA. We utilized a spectral analysis approach to find the naturally occurring dominant frequencies of oscillation in the incidence data using a Fast Fourier Transform (FFT) algorithm.

Results

Our study revealed four dominant peaks in the periodogram: the two most dominant peaks show a period of oscillation of 366 days and 146.4 days, while two smaller peaks indicate periods of 183 days and 122 days. The period of 366 days indicates that there is a single COVID-19 outbreak that occurs approximately once every year, which correlates with the dominant outbreak in the early/mid-winter months. The period of 146.4 days indicates approximately 3 peaks per year and matches well with each of the 3 annual outbreaks per year.

Conclusion

Our study revealed the predictable seasonality of COVID-19 outbreaks, which will guide public health preventative efforts to control future outbreaks. However, the methods used in this study cannot predict the amplitudes of the incidences in each outbreak: a multifactorial problem that involves complex environmental, social, and viral strain variables.

Effectiveness of influenza vaccination against coronavirus disease (COVID)-19 outcomes in hospitalized individuals in Brazil: an epidemiological study

OBJECTIVES

This study aimed to evaluate the impact of the flu vaccination on the mortality of hospitalized individuals with coronavirus disease (COVID)-19 in Brazil.

STUDY DESIGN

A retrospective cohort study was conducted based on epidemiological data released by the Brazilian Ministry of Health.

METHODS

An observational study was performed using epidemiological data available at OpenDataSUS. The primary outcome was death-the study period comprised December 29, 2019, to April 6, 2023. The odds ratio with a 95% confidence interval (OR; 95% CI) was calculated to evaluate the association between the epidemiological markers, including the vaccination status against influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the outcome using a multivariable analysis.

RESULTS

The study comprised 791,891 hospitalized individuals with COVID-19. In the study, male sex, older age, living in rural areas, and race (Black and Indigenous peoples), as well as the presence of clinical signs, comorbidities (except the presence of asthma, which was protective), need for intensive care unit, and invasive mechanical ventilation, were associated with a higher chance of death; the vaccination was protective. Among patients with COVID-19, the individuals who received vaccination against influenza [N = 138,564; OR = 0.754 (95% CI = 0.742-0.766)], SARS-CoV-2 [N = 114,628; OR = 0.630 (95% CI = 0.620-0.641)], or both vaccines [N = 55,616; OR = 0.544 (95% CI = 0.531-0.556)], when compared to the individuals who received no vaccination (N = 483,083), had a lower chance of death.

CONCLUSIONS

The flu vaccination might be responsible for decreased mortality in hospitalized patients with COVID-19 in Brazil.

Estimated Effectiveness of Coadministration of the BNT162b2 BA.4/5 COVID-19 Vaccine With Influenza Vaccine

Importance

No data comparing the estimated effectiveness of coadministering COVID-19 vaccines with seasonal influenza vaccine (SIV) in the community setting exist.

Objective

To examine the comparative effectiveness associated with coadministering the BNT162b2 BA.4/5 bivalent mRNA COVID-19 vaccine (BNT162b2-biv [Pfizer BioNTech]) and SIV vs giving each vaccine alone.

Design, Setting, and Participants

A retrospective comparative effectiveness study evaluated US adults aged 18 years or older enrolled in commercial health insurance or Medicare Advantage plans and vaccinated with BNT162b2-biv only, SIV only, or both on the same day between August 31, 2022, and January 30, 2023. Individuals with monovalent or another brand of mRNA bivalent COVID-19 vaccine were excluded.

Exposure

Same-day coadministration of BNT162b2-biv and SIV; receipt of BNT162b2-biv only (for COVID-19-related outcomes) or SIV only (for influenza-related outcomes) were the comparator groups. For adults aged 65 years or older, only enhanced SIVs were included.

Main Outcomes and Measures

COVID-19-related and influenza-related hospitalization, emergency department (ED) or urgent care (UC) encounters, and outpatient visits.

Results

Overall, 3 442 996 individuals (57.0% female; mean [SD] age, 65 [16.7] years) were included. A total of 627 735 individuals had BNT162b2-biv and SIV vaccine coadministered, 369 423 had BNT162b2-biv alone, and 2 445 838 had SIV alone. Among those aged 65 years or older (n = 2 210 493; mean [SD] age, 75 [6.7] years; 57.9% female), the coadministration group had a similar incidence of COVID-19-related hospitalization (adjusted hazard ratio [AHR], 1.04; 95% CI, 0.87-1.24) and slightly higher incidence of emergency department or urgent care encounters (AHR, 1.12; 95% CI, 1.02-1.23) and outpatient visits (AHR, 1.06; 95% CI, 1.01-1.11) compared with the BNT162b2-biv-only group. Among individuals aged 18 to 64 years (n = 1 232 503; mean [SD] age, 47 [13.1] years; 55.4% female), the incidence of COVID-19-related outcomes was slightly higher among those who received both vaccines vs BNT162b2-biv alone (AHR point estimate range, 1.14-1.57); however, fewer events overall in this age group resulted in wider CIs. Overall, compared with those who received SIV alone, the coadministration group had a slightly lower incidence of most influenza-related end points (AHR point estimates 0.83-0.93 for those aged ≥65 years vs 0.76-1.08 for those aged 18-64 years). Negative control outcomes suggested residual bias and calibration of COVID-19-related and influenza-related outcomes with negative controls moved all estimates closer to the null, with most CIs crossing 1.00.

Conclusions and Relevance

In this study, coadministration of BNT162b2-biv and SIV was associated with generally similar effectiveness in the community setting against COVID-19-related and SIV-related outcomes compared with giving each vaccine alone and may help improve uptake of both vaccines.

Key Considerations during the Transition from the Acute Phase of the COVID-19 Pandemic: A Narrative Review

The COVID-19 pandemic has been met with an unprecedented response from the scientific community, leading to the development, investigation, and authorization of vaccines and antivirals, ultimately reducing the impact of SARS-CoV-2 on global public health. However, SARS-CoV-2 is far from being eradicated, continues to evolve, and causes substantial health and economic burdens. In this narrative review, we posit essential points on SARS-CoV-2 and its responsible management during the transition from the acute phase of the COVID-19 pandemic. As discussed, despite Omicron (sub)variant(s) causing clinically milder infections, SARS-CoV-2 is far from being a negligible pathogen. It requires continued genomic surveillance, particularly if one considers that its future (sub)lineages do not necessarily have to be milder. Antivirals and vaccines remain the essential elements in COVID-19 management. However, the former could benefit from further development and improvements in dosing, while the seasonal administration of the latter requires simplification to increase interest and tackle vaccine hesitancy. It is also essential to ensure the accessibility of COVID-19 pharmaceuticals and vaccines in low-income countries and improve the understanding of their use in the context of the long-term goals of SARS-CoV-2 management. Regardless of location, the primary role of COVID-19 awareness and education must be played by healthcare workers, who directly communicate with patients and serve as role models for healthy behaviors.

Safety and Immunogenicity of the BNT162b2 Vaccine Coadministered with Seasonal Inactivated Influenza Vaccine in Adults

INTRODUCTION

Vaccination is a critical tool for preventing coronavirus disease 2019 (COVID-19) and influenza illnesses. Coadministration of the COVID-19 vaccine, BNT162b2, with seasonal inactivated influenza vaccine (SIIV) can provide substantial benefits, including streamlining vaccine delivery.

METHODS

In this phase 3 study, healthy 18- to 64-year-olds who had received three previous doses of BNT162b2 were randomized (1:1) to the coadministration group (month 0, BNT162b2 + SIIV; month 1, placebo) or the separate-administration group (month 0, placebo + SIIV; month 1, BNT162b2). The primary immunogenicity objective was to demonstrate that the immune responses elicited by BNT162b2 and SIIV [measured by full-length S-binding immunoglobulin G (IgG) levels and strain-specific hemagglutination inhibition assay (HAI) titers against four influenza strains 1 month post-vaccination, respectively] when coadministered were noninferior to those elicited by either vaccine administered alone, based on a prespecified 1.5-fold noninferiority margin [lower bound 95% CI for geometric mean ratio (GMR) > 0.67]. Reactogenicity and adverse event (AE) rates were evaluated.

RESULTS

Randomized participants who received study vaccination (N = 1128; coadministration group, n = 564; separate-administration group, n = 564) had a median age of 39 years. Model-adjusted GMRs for coadministration to separate administration were 0.83 (95% CI 0.77, 0.89) for full-length S-binding IgG levels and 0.89-1.00 (lower bound of all 95% CIs > 0.67) for the four influenza strain-specific HAI titers, with all endpoints achieving the prespecified noninferiority criterion. Reactogenicity events were mostly mild or moderate when BNT162b2 was coadministered with SIIV. Serious AEs were reported in < 1% of participants within 1 month after any vaccination; none were considered vaccine-related.

CONCLUSIONS

BNT162b2 coadministered with SIIV elicited immune responses that were noninferior to those elicited by BNT162b2 alone and SIIV alone, and BNT162b2 had an acceptable safety profile when coadministered with SIIV. The results of this study support the coadministration of BNT162b2 and SIIV in adults.

TRIAL REGISTRATION

ClinicalTrials.gov registration: NCT05310084.

Strong biological correlations as a cause of autonomous oscillations in epidemics

We consider the impact of strong biological correlations on the epidemic process. The biological correlations mean the influence of the environment on the individual state of immunity of the infected person. Accounting for the correlations turns the traditional SIRS model into the 3D Lotka-Volterra model, the parameters of which are uniquely determined by the parameters of the original SIRS model. The measure of the biological correlations in the epidemic is the correlation strength parameter [Formula: see text], where [Formula: see text] and [Formula: see text] are the duration of the infectious period of the disease and the duration of immunity, respectively, both measured in years. If the epidemic is highly correlated ([Formula: see text]), then after the first epidemic outbreak, subsequent oscillations occur, the period [Formula: see text] of which is less than one year. The example is the COVID-19 pandemic. If the epidemic is weakly correlated ([Formula: see text]), the period [Formula: see text] of the oscillations is more than one year. Then in the presence of regular annual outbreaks the oscillations do not have time to manifest themselves. The examples are the ordinary flu annual epidemics. In the absence of the annual epidemic factor, the oscillations can exist and persist regardless of the [Formula: see text] value. The examples are the measles epidemics. The 3D Lotka-Volterra model makes it possible to predict the period [Formula: see text] of the future oscillations based on two known clinical parameters-[Formula: see text] and [Formula: see text]. This period turns out to be equal to 2π multiplied by the geometric mean of the duration of the infectious period of the disease [Formula: see text] and the duration of immunity [Formula: see text]. The adequacy of the 3D Lotka-Volterra model is supported by examples of the 2017-2019 annual flu epidemics and the 2020-2022 COVID-19 epidemic in Israel, as well as the succession of measles epidemics in the UK between 1940 and 1970.

An Updated Systematic Review and Meta-Analysis of the Association between the De Ritis Ratio and Disease Severity and Mortality in Patients with COVID-19

Patients with Coronavirus disease 2019 (COVID-19) often have elevations in markers of liver injury, particularly serum aspartate transaminase (AST) and alanine transaminase (ALT). Such alterations may affect the AST/ALT ratio (De Ritis ratio) and, potentially, clinical outcomes. We conducted an updated systematic review and meta-analysis of the association between the De Ritis ratio and COVID-19 severity and mortality in hospitalized patients. PubMed, Web of Science, and Scopus were searched between 1 December 2019 and 15 February 2023. The Joanna Briggs Institute Critical Appraisal Checklist and the Grading of Recommendations, Assessment, Development, and Evaluation were used to assess the risk of bias and the certainty of the evidence, respectively. Twenty-four studies were identified. The De Ritis ratio on admission was significantly higher in patients with severe disease and non-survivors vs. patients with non-severe disease and survivors (15 studies, weighted mean difference = 0.36, 95% CI 0.24 to 0.49, p < 0.001). The De Ritis ratio was also associated with severe disease and/or mortality using odds ratios (1.83, 95% CI 1.40 to 2.39, p ˂ 0.001; nine studies). Similar results were observed using hazard ratios (2.36, 95% CI 1.17 to 4.79, p = 0.017; five studies). In six studies, the pooled area under the receiver operating characteristic curve was 0.677 (95% CI 0.612 to 0.743). In our systematic review and meta-analysis, higher De Ritis ratios were significantly associated with severe disease and mortality in COVID-19 patients. Therefore, the De Ritis ratio can be useful for early risk stratification and management in this patient group (PROSPERO registration number: CRD42023406916).

Changes in the epidemiological profile of SARS-CoV-2-positive individuals in Mexico across pandemic waves as an explanation of fatality reduction: a retrospective observational study

OBJECTIVES

We aim to quantify shifts in hospitalisation and mortality and how those were related to the first three phases of the epidemic and individuals' demographics and health profile among those with a positive test for SARS-CoV-2 treated at the Mexican Social Security Institute's facilities from March 2020 to October 2021.

DESIGN

Retrospective observational study using interrupted time series analysis to identify changes in hospitalisation rate and case fatality rate (CFR) by epidemic wave.

SETTING

Data from the Mexican Institute of Social Security's (IMSS) Online Influenza Epidemiological Surveillance System (SINOLAVE) that include all individuals that sought care at IMSS facilities all over Mexico.

PARTICIPANTS

All individuals included in the SINOLAVE with a positive PCR or rapid test for SARS-CoV-2.

PRIMARY AND SECONDARY OUTCOME MEASURES

Monthly test positivity rates, hospitalisation rates, CFRs and prevalence of relevant comorbidities by age group.

RESULTS

From March 2020 to October 2021, the CFR declined between 1% and 3.5%; the declines were significant for those 0-9, 20-29, 30-39, 40-49 and 70 and older. The decline was steep during the first wave and was less steep or was temporarily reversed at the beginning of the second and third waves (changes in the trend of about 0.3% and 3.8%, and between 0.7% and 3.8%, respectively, for some age groups), but then continued to the end of the analytical period. Prevalence of diabetes, hypertension and obesity among patients testing positive also declined-two for most age groups (reductions of up to 10 percentage points for diabetes, 12 percentage points for hypertension and 19 percentage points for obesity).

CONCLUSION

Data suggest that the decrease in COVID-19 fatality rate is at least partially explained by a change in the profile of those contracting the disease, that is, a falling proportion of individuals with comorbidities across all age groups.