Since the emergence of COVID-19, the forecasting of new daily positive cases and deaths has been one of the essential elements in policy setting and medical resource management worldwide. An essential factor in forecasting is the modeling of susceptible populations and vaccination effectiveness (VE) at the population level. Owing to the widespread viral transmission and wide vaccination campaign coverage, it becomes challenging to model the VE in an efficient and realistic manner, while also including hybrid immunity which is acquired through full vaccination combined with infection. Here, the VE model of hybrid immunity was developed based on an in vitro study and publicly available data. Computational replication of daily positive cases demonstrates a high consistency between the replicated and observed values when considering the effect of hybrid immunity. The estimated positive cases were relatively larger than the observed value without considering hybrid immunity. Replication of the daily positive cases and its comparison would provide useful information of immunity at the population level and thus serve as useful guidance for nationwide policy setting and vaccination strategies.

As of May 2022, a new outbreak of the human monkeypox (MPOX) disease appeared in multiple countries, where the 2022 human MPOX disease spread to more than 109 cases, excluding the suspected cases up to the end of 2022. The deaths of the 2022 human MPOX exceeded 200 cases up to the same date. The human MPOX is not a new disease, this disease was once endemic in some countries on the African continent. Despite this, this disease began to spread in a number of countries around the world in 2022. The first case of the 2022 human MPOX was recorded in the United Kingdom in May. After that date, this disease began to become a pandemic in a number of other countries, such as the United States, Spain, and Brazil. The 2022 human MPOX is a type of viral disease caused by a viral virus, the MPOX virus, and this virus causes rashes and lesions over the skin of the patient, as well as in the mouth of the patient. Multiple effective indicators are employed for the study of the 2022 of the human MPOX, such as the herd immunity of the human MPOX (HIhMPOX), the basic reproduction number of the human MPOX (BRNhMPOX), and the infection period of the human MPOX. This study focuses on the study of the herd immunity of, and the basic reproduction number of the 2022 outbreak of human MPOX in multiple countries around the world. This study employed the semianalytical method of the Susceptible compartment S, Infectious compartment I, Recovered compartment R (SIR) pandemic model including the mortality for the study of the herd immunity, and the basic reproduction number of the 2022 human MPOX disease. It is found that the average value of the herd immunity for the human MPOX disease in 2022 equals to 0.2194, that is, 21.94% for multiple countries, and equals to 35.52% for the United States, and 30.99% for Spain. Also, it is found that the average value of the basic reproduction number of the 2022 human MPOX disease equals to 1.2810 for multiple countries. It is concluded from these values that 21.94% of the total susceptible population has to be immunized in an effective way to prevent the spreading of the disease. Also, based on the previous values, it is concluded that the status of the 2022 MPOX disease is spreading as a pandemic.

African swine fever (ASF) is a highly contagious disease that is caused by the ASF virus (ASFV) with a high fatality rate in domestic pigs resulting in a high socio-economic impact. The pig business in Vietnam was recently affected by ASF for the first time. This study thus aimed to develop a disease dynamic model to explain how ASFV spreads in Vietnamese pig populations and suggest a protective vaccine coverage level required to prevent future outbreaks. The outbreak data were collected from ten private small-scale farms within the first wave of ASF outbreaks in Vietnam. Three methods were used to estimate the basic reproduction number (R0), including the exponential growth method, maximum likelihood method, and attack rate method. The average R0 values were estimated at 1.49 (95%CI: 1.05-2.21), 1.58 (95%CI: 0.92-2.56), and 1.46 (95%CI: 1.38-1.57), respectively. Based on the worst-case scenario, all pigs in a herd would be infected and removed within 50 days. We suggest vaccinating at least 80% of pigs on each farm once a commercially approved ASF vaccine is available. However, an improvement in biosecurity levels in small-scale farms is still greatly encouraged to prevent the introduction of the virus.

For epidemics such as COVID-19, with a significant population having asymptomatic, untested infection, model predictions are often not compatible with data reported only for the cases confirmed by laboratory tests. Additionally, most compartmental models have instantaneous recovery from infection, contrary to observation. Tuning such models with observed data to obtain the unknown infection rate is an ill-posed problem. Here, we derive from the first principle an epidemiological model with delay between the newly infected (N) and recovered (R) populations. To overcome the challenge of incompatibility between model and case data, we solve for the ratios of the observed quantities and show that log(N(t)/R(t)) should follow a straight line. This simple prediction tool is accurate in hindcasts verified using data for China and Italy. In traditional epidemiology, an epidemic wanes when much of the population is infected so that \'herd immunity\' is achieved. For a highly contagious and deadly disease, herd immunity is not a feasible goal without human intervention or vaccines. Even before the availability of vaccines, the epidemic was suppressed with social measures in China and South Korea with much less than 5% of the population infected. Effects of social behaviour should be and are incorporated in our model.

The COVID-19 pandemic caused by SARS CoV-2 is a worldwide emergency, and is taking a substantial toll on human health, lives, and the global economy. Due to the novelty of this virus, no SARS CoV-2-specific treatments or licensed vaccines are available though few vaccines are undergoing clinical trials. Therefore, continued research into an effective vaccine is an urgent necessity. The reinfection of recovered patients is one of the major concerns of healthcare providers worldwide. Health authorities are currently seeking evidence of protection from reinfection in recovered individuals. This is the first case report in Saudi Arabia on a patient who was diagnosed as COVID-19-positive; recovered; and after successful recovery was protected against reinfection.

Since 2017, 10 vaccines are compulsory for newborns in Italy and unvaccinated children are not admitted to kindergartens. Recently the Italian Government announced the perspective of reforming the law about the compulsory vaccination. A debated started about the presence, in the same class of the schools, of unvaccinated and immunocompromised children. Cancer is the one of the most important cause of immunodepression among children: after the chemoterapy, there is a period of 13-23 months in which the cancer survivors have to come back at the school and at to the \"normal life\" (even for psychological exigency) but remain at risk of infectious disease for the immunodepression. The most important chance to protect this subgroup of patients remains the herd immunity.

We estimated the direct, indirect and total effects of the 13-valent pneumococcal conjugate vaccine (PCV13) on invasive pneumococcal disease (IPD) in children. A population-based cohort study followed children aged between 2.5 and 59 months between 2001 and 2014 in Navarra, Spain. IPD incidence was compared by PCV status and period. All cases diagnosed from July 2010 to December 2014 and eight matched controls per case were analysed to estimate the adjusted direct effect of PCV13. A total of 120,980 children were followed and 206 IPD cases were detected. Compared with unvaccinated children in the baseline period (2001-2004), overall IPD incidence in 2011-2014 (76% average PCV coverage) declined equally in vaccinated (total effect: 76%; hazard ratio (HR): 0.24; 95% confidence interval (CI): 0.14-0.40) and unvaccinated children (indirect effect: 78%; HR: 0.22; 95% CI: 0.09-0.55). IPD incidence from non-PCV13 serotypes increased among vaccinated children (HR: 2.84; 95% CI: 1.02-7.88). The direct effect of one or more doses of PCV13 against vaccine serotypes was 95% (odds ratio: 0.05; 95% CI: 0.01-0.55). PCV13 was highly effective in preventing vaccine-serotype IPD. The results suggest substantial and similar population-level vaccine benefits in vaccinated and unvaccinated children through strong total and indirect effects.