Forecast of omicron wave time evolution

Adopting an early doubling time of three days for the rate of new infections with the omicron mutant the temporal evolution of the omicron wave in different countries is predicted. The predictions are based on the susceptible-infectious-recovered/removed (SIR) epidemic compartment model with a constant stationary ratio k=mu(t)/a(t) between the infection (a(t)) and recovery (mu(t)) rate. The fixed early doubling time then uniquely relates the initial infection rate a0 to the ratio k, which therefore determines the full temporal evolution of the omicron waves. For each country three scenarios (optimistic, pessimistic, intermediate) are considered and the resulting pandemic parameters are calculated. These include the total number of infected persons, the maximum rate of new infections, the peak time and the maximum 7-day incidence per 100000 persons. Among the considered European countries Denmark has the smallest omicron peak time and the recently observed saturation of the 7-day incidence value at 2478 is in excellent agreement with the prediction in the optimistic scenario. For Germany we predict peak times of the omicron wave ranging from 32 to 38 and 45 days after the start of the omicron wave in the optimistic, intermediate and pessimistic scenario, respectively, with corresponding maximum SDI values of 7090, 13263 and 28911, respectively. Adopting Jan 1st, 2022 as the starting date our predictions implies that the maximum of the omicron wave is reached between Feb 1 and Feb 15, 2022. Rather similar values are predicted for Switzerland. Due to an order of magnitude smaller omicron hospitalization rate, due to the high percentage of vaccinated and boostered population, the German health system can cope with maximum omicron SDI value of 2800 which is about a factor 2.5 smaller than the maximum omicron SDI value 7090 in the optimistic case. By either reducing the duration of intensive care during this period of maximum, and/or by making use of the nonuniform spread of the omicron wave across Germany, it seems that the German health system can barely cope with the omicron wave avoiding triage decisions. The reduced omicron hospitalization rate also causes significantly smaller mortality rates compared to the earlier mutants in Germany. In the optimistic scenario one obtains for the total number of fatalities 7445 and for the maximum death rate 418 per day which are about one order of magnitude smaller than the beta fatality rate and total number.

Clinical Presentation, Laboratory Findings, Complications, and Mortality of Influenza During the Epidemic of October 2019-February 2020 in Iran

Background: Influenza is one of the most important viruses and causes millions of infections and 290-600 thousands deaths annually. We aimed to evaluate the hospitalization rates due to complications caused by the influenza virus (pneumonia, seizures, sinusitis, otitis, myositis and encephalitis), the frequency of clinical signs, and laboratory findings in children under 15 years of age infected with Influenza.Methods: We conducted a cross-sectional study during the Influenza epidemic in Qom, Iran, from October 2019 to February 2020. Children under 15 years of age with the definitive diagnosis of influenza obtained by polymerase chain reaction (PCR) test were included.Results: Out of 1225 patients who referred to us with flu-like symptoms; 1172 patients were referred by the emergency department and our hospital clinic but 53 patients were referred to us by other paediatricians. 375 patients (30.61%) who had a positive PCR test result for influenza and suffered from complications caused by the virus were hospitalized.The number of male hospitalized patients was 231 (61.6% of hospitalized patients) and the number of female hospitalized patients was 144 (38.4% of hospitalized patients) respectively.The highest age range of patients with pneumonia was of 13 months to 3 years with a hospitalization rate of 36.41% and the lowest hospitalization rate was of 12 years to 15 years with a hospitalization rate of 0.84%.The most serious complication observed in patients caused by the influenza virus was pneumonia; with 17 cases (4.53%) reported.89.6% of patients had fever at the time of referral causing it to be the most common clinical symptom among patients. Cough ranked second with 76.8%.Lymphopenia and leukopenia was recognized as the most common laboratory findings with a frequency of 26.33% and 21.85%.Conclusions: Complications of influenza was not uncommon in children and affected a fifth of the patients. The influenza epidemic of October 2019- February 2020 imposed a heavy burden on our hospital and the learned lessons should be implemented to further assist the physicians in future influenza epidemic.

Clinical and laboratory findings of COVID-19 in children younger than six months old; Neutropenia is more common not lymphopenia

Background: Studies on age-related differences in clinical and laboratory features on coronavirus disease 2019 (COVID-19) are limited. We aimed to evaluate the demographic, clinical, and laboratory findings of COVID-19 in children younger than six months old and compare them with older children. Methods: A single-center retrospective study, including 209 confirmed COVID-19 cases, was conducted between March 11, 2020, and September 1, 2021. The case group consisted of 47 patients younger than six months old, and the control group consisted of 162 patients older than six months old. Results: The mean age of the case group was 2.77±1.52 months, and the control group was 101.89±65.77 months. Cough was statistically higher in the control group, poor feeding was higher in the case group (P=.043, .010). The underlying disease ratio was statistically higher in the case group; however, the hospitalization rate was higher in the case group (P=.001, .036). The case group had significantly lower median values of the absolute neutrophil count, hemoglobin, and higher median values of white blood cell, absolute lymphocyte count, platelet than the control group (P<.05). C-reactive protein, fibrinogen values were significantly lower, and procalcitonin, D-dimer, troponin T, N‑terminal pro-B-type natriuretic peptide significantly higher in the case group (P<.05). Lymphopenia was more common in the control group, whereas neutropenia was more common in the case group (P= .001, .011). Conclusions: We showed that most children younger than six months old had mild and asymptomatic COVID-19; however, the hospitalization rate was higher, and neutropenia was more common than older children.

Modeling The Impact of Vaccination On COVID-19 And Its Delta Variant

Vaccination is an important means to fight against the spread of the SARS-CoV-2 virus and its variants. In this work, we propose a general susceptible-vaccinated-exposed-infected-hospitalized-removed (SVEIHR) model and derive its basic and effective reproduction numbers. We set Hong Kong as an example to prove the validity of our model. The model shows how the number of confirmed COVID-19 cases in Hong Kong during the second and third waves of the COVID-19 pandemic would have been reduced had vaccination been available then. We then investigate the relationships between various model parameters and the cumulative number of hospitalized COVID-19 cases in Hong Kong for the ancestral and Delta strains of the virus. Next, we compare the evolution of the SVEIHR model to the traditional “herd immunity” threshold where the proportion of vaccinated individuals is static and no further vaccination takes place after model initialization. Numerical results for Hong Kong demonstrate that the static herd immunity threshold corresponds to a cumulative hospitalization ratio of about one percent (assuming the current hospitalization rate of infected individuals is maintained). We also demonstrate that when the vaccination rate is high, the initial proportion of vaccinated individuals can be lowered for while still maintaining the same proportion of cumulative hospitalized individuals.

Has Clinical and Epidemiological Varicella Burden Changed over Time in Children? Overview on Hospitalizations, Comorbidities and Costs from 2010 to 2017 in Italy

According to WHO estimates, varicella disease is responsible of a worldwide significant burden in terms of hospitalizations, complications, and deaths, with more than 90% of cases under 12 years old. This study aims at evaluating the clinical, epidemiological, and economic burden of varicella in Ligurian children, about comorbidities, organizational variables, and vaccination coverages from 2010 to 2017, in terms of Emergency Department accesses and hospitalizations. The overall hospitalization rate was 179.76 (per 100,000 inhab.), with a gradual but significant decline since 2015, when universal varicella vaccination was introduced in Liguria (p < 0.0001). The risk of being hospitalized for complicated varicella in subjects with at least one comorbidity was significantly higher than in subjects without comorbidities (p = 0.0016). The economic analysis showed higher costs in subjects with complicated varicella who were 0–3 years old. This age group showed higher costs also considering extra-hospital costs for both outpatient procedures and pharmaceutical costs (p < 0.0001). The results confirm the relevant burden of varicella, especially in the 0–3 age group and in children with comorbidities. Thus, vaccination with the achievement of adequate vaccination coverages is confirmed to be a necessary control strategy to reduce hospitalizations and associated complications with important economic benefits.

Hospitalization Rate of Respiratory Syncytial Virus associated Acute Lower Respiratory Infection among Young Children in Suzhou, China, 2010-2014

Background: Data on disease burden of respiratory syncytial virus (RSV) associated acute lower respiratory infection (ALRI) among young children are limited in China. This study aimed to estimate the hospitalization rate of RSV-associated ALRI (RSV-ALRI) among children aged 0~59 months in Suzhou, China. Methods: We retrospectively identified all hospitalized ALRI children aged 0~59 months in Suzhou University Affiliated Children’s Hospital during January 2010 to December 2014. Detailed diagnosis and treatment data were collected by individual medical chart review. Referring to WHO influenza disease burden estimation method, we estimated the hospitalization rate of RSV-ALRI among children aged 0~59 months in Suzhou, China. Results: Among 28,209 ALRI cases, 19,317 (68.5%) were tested for RSV and the RSV positive proportion was 21.3% (4,107/19,317). The average hospitalization rate of RSV-ALRI for children aged 0~59 months was 14 (95% confidence interval [CI]:14~14)/1,000 children-years, for children aged 0~5, 6~11, 12~23, and 24~59 months were 70 (95%CI: 67~73), 31 (95%CI: 29~33), 11 (95%CI: 10~12), and 3 (95%CI: 3~3) /1,000 children-years, respectively. Conclusion: There is considerable RSV-ALRI hospitalization among children aged 0~59 months, particularly among children aged <1 years. An effective monoclonal antibody or vaccine is urgently needed to address the substantial hospitalization burden owing to RSV infection. Key words: Respiratory syncytial virus, Hospitalization rate, Acute lower respiratory infection, Children, China

Optimal control for dengue eradication program under the media awareness effect

In this article, a mathematical model is proposed to assess the effects of media awareness on dengue eradication programs. First, the existence and local stability of equilibrium points are discussed using the concept of the basic reproduction number. Using the center-manifold theorem, it is shown that the proposed model always undergoes a forward bifurcation at the basic reproduction number equal to unity. It is observed that the high-intensity media awareness could reduce the size of the endemic equilibrium. Based on local sensitivity analysis, we identify the three most sensitive parameters, namely the natural death rate of mosquito (μ v ), infection rates (β h1, β v1), and hospitalization rate (η). Hence, control variables need to be introduced to increase/reduce these parameters. In this article, we use three different control variables, namely the media campaign, (u 1(t)), to reduce infection rates, additional hospitalization rate, (u 2(t)), and fumigation rate, (u 3(t)), to increase mosquitoes death rate. Pontryagin’s maximum principle is used to determine the optimal conditions. Some numerical simulations are performed to describe a possible scenario in the field. Cost effectiveness analysis is then conducted to determine the best strategy for the dengue eradication program. We conclude that a combination of media campaigns and fumigation is the most effective strategy to prevent a significant increase in the number of infected individuals.

Hospitalizations related to meningococcal infection in Spain from 1997 to 2018

Background Baseline hospitalization, mortality, and in-hospital fatality rates for meningococcal infection are required to evaluate preventive interventions, such as the inclusion of the conjugated quadrivalent meningococcal vaccine and serogroup B based protein vaccines. Methods All meningococcal infection–related hospitalizations in any diagnostic position in Spain from 1st January 1997 through 31st December 2018 were analysed. The annual hospitalization rate, mortality rate and case-fatality rate were calculated. Results The average hospitalization rate for meningococcal infection was 1.64 (95% CI 1.61 to 1.66) hospitalizations per 100,000 inhabitants during the study period and significantly decreased from 1997 to 2018. Hospitalizations for meningococcal infection decreased significantly with age and were concentrated in children under 5 years of age (46%). The hospitalization rates reached 29 per 100,000 and 24 per 100,000 children under 1 and 2 years of age, respectively. The in-hospital case-fatality rate was 7.45% (95% CI 7.03 to 7.86). Thirty percent of the deaths occurred in children under 5 years of age, and more than half occurred in adults. The case fatality rate increased significantly with age (p < 0.001). Conclusion It is necessary to maintain epidemiological surveillance of meningococcal infection to determine the main circulating serogroups involved, track their evolution, and evaluate preventive measures whose effectiveness must be assessed in all age groups.