Hospital morbidity among elderly patients, before and after influenza vaccination in the state of Paraná

[Post-vaccination adverse events in the elderly in the State of São Paulo, Brazil, 2015 to 2017]

Vaccination is one of the public health measures that has most contributed to decreasing the incidence of vaccine-preventable diseases. However, vaccines can lead to post-vaccination adverse events. This study thus aimed to analyze the prevalence of post-vaccination adverse events in elderly persons, determine the reported post-vaccination adverse events, identify the vaccines that cause post-vaccination adverse events, and verify the post-vaccination adverse events and vaccines that lead to hospitalizations in the State of São Paulo, Brazil, from 2015 to 2017. This was a descriptive cross-sectional study with a quantitative approach based on notifications of post-vaccination adverse events recorded in the Information System of the National Immunization Program. The results showed that of the 15,196,080 elderly persons that were immunized, there were 207 reports of post-vaccination adverse events, of which 187 (89%) were non-serious adverse events and 15 (8%) due to immunization errors (IE). The majority of the patients were female (86%), white (49%), and from 60 to 69 years of age (70%). Clinical manifestations featured local reactions at the injection site (84%). There were 131 cases (64%) that evolved to cure without sequelae. Two individuals (2%) were hospitalized due to serious adverse events. The first had received adult diphtheria/tetanus (dT), pneumococcal (Pn23), and influenza vaccines, and the second had received Pn23. The post-vaccination adverse events notifications showed incomplete information. In conclusion, notification of post-vaccination adverse events is essential. Health professionals need to be committed to adequate completion of the notification forms, with health surveillance supervision aimed at quality of care for elderly persons with post-vaccination adverse events.

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics - a systematic literature review

AIM

The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries.

METHOD

Global health databases were searched in three thematic areas - policy, availability and protective benefits in the context of human seasonal influenza vaccine in the tropics and subtropics. We excluded studies on monovalent pandemic influenza vaccine, vaccine safety, immunogenicity and uptake, and disease burden.

RESULTS

Seventy-four countries in the tropics and subtropics representing 60% of the world's population did not have a national vaccination policy against seasonal influenza. Thirty-eight countries used the Northern Hemisphere and 21 countries the Southern Hemisphere formulation. Forty-six countries targeted children and 57 targeted the elderly; though, the age cut-offs varied. Influenza vaccine supply increased twofold in recent years. However, coverage remained lower than five per 1000 population. Vaccine protection against laboratory-confirmed influenza in the tropics ranged from 0% to 42% in the elderly, 20-77% in children and 50-59% in healthy adults. Vaccinating pregnant women against seasonal influenza prevented laboratory-confirmed influenza in both mothers (50%) and their infants <6 months (49-63%).

CONCLUSION

Guidelines on vaccine composition, priority risk groups and vaccine availability varied widely. The evidence on vaccine protection was scarce. Countries in the tropics and subtropics need to strengthen and expand their evidence-base required for making informed decisions on influenza vaccine introduction and expansion, and how much benefit to expect.

Ecological study on mortality from influenza and pneumonia before and after influenza vaccination in the Northeast and South of Brazil

The study compared mortality from influenza and pneumonia in elderly people (65 years or older) before and since implementation of influenza vaccination in the South and Northeast regions of Brazil. Official population and mortality data were retrieved from government agencies to estimate weekly mortality rates. The Serfling model was used to identify influenza outbreaks and estimate the mortality attributable to them. In the South, the vaccination period showed a major reduction in mortality from influenza and pneumonia and in the number and duration of influenza outbreaks. These results were interpreted as consistent with the hypothesis of the vaccination program's effectiveness. In the Northeast, there was an increase in mortality from influenza and pneumonia during vaccination, which was associated with a quality improvement in recording causes of death in the elderly. An increase was also seen in mortality attributable to influenza outbreaks, suggesting a mismatch between the period in which vaccination is conducted and the relevant climatic characteristics for influenza transmission.

[Factors related to death by the Pandemic Influenza A (H1N1) 2009 in patients treated with oseltamivir]

This study aimed to identify factors related to death in Pandemic Influenza A(H1N1)2009 in patients treated with Oseltamivir. It is an observational and retrospective study, carried out with data of patients who had presented laboratorial diagnosis of the illness. Data were collected from the notification forms of the disease, belonging to a database of the Ministry of Health. Statistical analysis was performed by chi-square, Student t test and logistic regression, considering significant p values <0,05. The highest mortality was observed in patients aged between 20 and 59 years, low schooling, with the presence of comorbidities, not vaccinated, treated late and had more severe symptoms of infection. The identification of risk factors for death reinforces the need for prevention and early care, especially in the presence of factors that increase the clinical severity of disease.

Effectiveness of the Brazilian influenza vaccination policy, a systematic review

Since 1999, Brazil has undertaken annual influenza vaccine campaigns, free of charge, targeting the elderly population, health professionals, and immune-deficient patients. We conducted a systematic review of literature in order to evaluate the effectiveness of the initiative. We used the keywords influenza, vaccine, Brazil and effectiveness to search the main databases. Thirty-one studies matched our inclusion and exclusion criteria. Influenza vaccine coverage among the elderly is high, though not as high as suggested by the official figures. Estimates on effectiveness are scarce. The majority come from ecological studies that show a modest reduction in mortality and hospital admissions due to influenza-related causes. Such reduction is not evident in the North and Northeastern states of Brazil, a finding that is probably related to the different seasonal pattern of influenza in equatorial and tropical regions. Brazilian epidemiologists still owe society better-designed studies addressing the effectiveness of influenza vaccine campaigns.