Mozhgan Seif; Mehdi Sharafi; Marziyeh Sadat Seif; Mohsen Bayati; Jalal Karimi
Abstract
Background: The effectiveness of COVID-19 vaccination determines the resource allocation for saving lives in this pandemic. Certainly, the efficacy of all vaccines has been studied in laboratory situations. However, the present study aims to estimate the effectiveness of vaccination in real conditions ...
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Background: The effectiveness of COVID-19 vaccination determines the resource allocation for saving lives in this pandemic. Certainly, the efficacy of all vaccines has been studied in laboratory situations. However, the present study aims to estimate the effectiveness of vaccination in real conditions of Iranian populations by controlling the effect of demographic factors and the history of chronic diseases.Methods: This historical cohort study used information on 1988 hospitalized COVID-19 patients with less than 93% blood oxygen levels. Cox regression, Survival Tree, and Forests were applied to estimate the effect of immunity from vaccination on survival, while the effect of demographic characteristics and history of chronic diseases was controlled.Results: The analysis showed that 10% of the patients were immunized, while the Sinopharm vaccine and the rest by Sputnik induced 86% of the immunity. Although there was no difference in the effectiveness of the vaccines, it was found that the immunity from each vaccine increased survival. Patient age was identified as the most influential factor in survival. Other contributing factors include the history of opium/smoking, cancer, the history of chronic lung disease, kidney disease, high blood pressure, and cardiovascular problems.Conclusion: Although age is the most influential factor in patient survival, immunity can control the risk of COVID-19. Therefore, it is recommended to prioritize the old and patients with any of the above underlying problems for vaccination and timely treatment.
Itse Olaoye; Akinola Ayoola Fatiregun; Adewale M. Adejugbagbe; Modupeola Dosumu; Ekun Opeyemi; Zubairu Mahmud; David Adeleke; Tsemaye Jacdonmi; Aladesawe Talaat Adesokeji; Famokun Gboyega; Abiona Samuel
Abstract
Background: Yellow fever (YF) is an acute viral hemorrhagic fever caused by the yellow fever virus and transmitted by Aedes mosquito species. Despite the availability of a very effective vaccine, yellow fever virus (YFV) remains a public health threat across Africa. Enhanced disease surveillance, vector ...
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Background: Yellow fever (YF) is an acute viral hemorrhagic fever caused by the yellow fever virus and transmitted by Aedes mosquito species. Despite the availability of a very effective vaccine, yellow fever virus (YFV) remains a public health threat across Africa. Enhanced disease surveillance, vector control, and high vaccination coverages are key to the prevention and control of YF. This paper aimed to describe yellow fever surveillance in Ondo state and the outbreak investigation activities conducted in the LGAs where outbreaks occurred in the year 2021.Methods: This is a retrospective cross-sectional study. We conducted an epidemiological investigation of yellow fever suspected and confirmed cases in Ondo State in Nigeria in 2021, using the YF case-based surveillance data. We described outbreak investigation and response activities carried out in affected LGAs, where the outbreaks were confirmed.Results: A total of 62 suspected YF cases were reported from January to December 2021, with no record of mortality. More than half (53%) of the cases were between the age of 15 to 29 years. About three-quarter of the reported cases (73%) had received the YF vaccine. The overall attack rate was 1.33 cases per 100,000 population. Only 3 out of the 62 reported cases were confirmed as yellow fever cases.Conclusion: The resurgence of yellow fever in the state puts the state at high-risk for yellow fever transmission. To reduce the immediate risks to the health of the population, specific activities should be tailored towards increasing awareness on yellow fever transmission, prevention, and control. These include activities on risk communication and community engagement, active surveillance, vector control, strengthening of routine immunization, as well as continued implementation of preventive mass vaccination campaigns.
