Pneumococcal vaccine in the elderly: a useful but forgotten vaccine

Food Insecurity and Influenza and Pneumonia Vaccines Uptake Among Community-Dwelling Older Adults in the United States

Influenza and pneumonia vaccines can reduce morbidities and mortality associated with infectious diseases among older adults. Food security, good nutrition, and high-quality diets are critical for the wellbeing of older adults. However, little is known about the relationship between food insecurity and use of preventive health services, such as influenza and pneumonia vaccinations, among older adults. In this study, we analyzed data on 40,555 adults aged ≥ 65 years from the 2014-2018 National Health Interview Survey in the United States. Through multiple hierarchical logistic regression models, we investigated the associations between food insecurity and influenza and pneumonia vaccines uptake in this population. We found that, during 2014-2018, about 12.6 million (5.3%) adults aged ≥ 65 years lived in food-insecure households in the United States. Of those, 60.6% reported getting an influenza vaccine in the past 12 months, and 54.2% reported ever getting a pneumonia vaccine. Compared to food-secure older adults, food-insecure individuals were not significantly different in terms of influenza vaccine uptake. However, they were 25% less likely to have ever gotten a pneumonia vaccine (adjusted odds ratio = 0.75, 95% CI 0.65-0.86, P < .001). Efforts should be made to develop strategies to improve immunization rates among food-insecure older adults. Healthcare providers could routinely assess their vaccination status and screen them for food insecurity. Also, community level screening and intervention programs should target food-insecure older adults, who often face structural disadvantages. Future studies could explore and identify the underlying predictive factors contributing to low pneumonia vaccination rates among food-insecure older adults.

The impact of pneumococcal vaccination on pneumonia mortality among the elderly in Japan: a difference-in-difference study

BACKGROUND

It is plausible that the routine immunization among infants using pneumococcal conjugate vaccine 13 (PCV13) from 2013 and among the elderly using pneumococcal polysaccharide vaccine 23 (PPV23) from 2014 contributed to reducing the pneumonia mortality among the elderly in Japan. The present study aimed to estimate the causal effect of this vaccination on pneumonia mortality, using the available cause-of-death data and employing a difference-in-difference (DID) design.

METHODS

Two types of mortality data, that is, prefecture-dependent and age- and gender-specific mortality data, from 2003 to 2017 were retrieved. We used mortality due to malignant neoplasm and heart disease as control groups and employed a DID design with an assumed parallel mortality trend between pneumonia and control group mortality since 2013 to estimate the causal effect of pneumococcal vaccination from 2014.

RESULTS

Our estimation based on malignant neoplasm and heart disease as controls indicated that the reduced pneumonia mortality in 2017 owing to pneumococcal vaccination was as large as 41.9 (33.2, 50.6) and 31.2 (23.8, 38.6) per 100,000 individuals, respectively. The largest mortality reduction was observed for the oldest group (aged ≥90 years), especially among men.

DISCUSSION

The pneumococcal vaccination program, perhaps mainly represented by high vaccination coverage of PCV13 among children and partly by PPV23 administration with low coverage among the elderly in Japan, was shown to have reduced the pneumonia mortality in the elderly at the population level.

Age-Related Decline in Natural IgM Function: Diversification and Selection of the B-1a Cell Pool with Age

Streptococcus pneumoniae is the most common cause of pneumonia, which claims the lives of people over the age of 65 y seven times more frequently than those aged 5-49 y. B-1a cells provide immediate and essential protection from S. pneumoniae through production of natural Ig, which has minimal insertion of N-region additions added by the enzyme TdT. In experiments with SCID mice infected with S. pneumoniae, we found passive transfer of IgG-depleted serum from aged (18-24 mo old) mice had no effect whereas IgG-depleted serum from young (3 mo old) mice was protective. This suggests protective natural IgM changes with age. Using single cell PCR we found N-region addition, which is initially low in fetal-derived B-1a cell IgM developing in the absence of TdT, increased in 7- to 24-mo-old mice as compared with 3-mo-old mice. To determine the mechanism responsible for the age related change in B-1a cell IgM, we established a mixed chimera system in which mice were reconstituted with allotype-marked mature peritoneal B-1a cells and adult bone marrow cells. We demonstrated even in the presence of mature peritoneal B-1a cells, adult bone marrow contributed to the mature B-1a cell pool. More importantly, using this system we found over a 10-mo-period peritoneal B-1a cell IgM changed, showing the number of cells lacking N-region additions at both junctions fell from 49 to 29% of sequences. These results strongly suggest selection-induced skewing alters B-1a cell-derived natural Ab, which may in turn be responsible for the loss of natural IgM-mediated protection against pneumococcal infection.

Assessing the Immunogenic Response of a Single Center's Pneumococcal Vaccination Protocol in Sickle Cell Disease

Sickle cell disease (SCD) is the most common inherited hematologic disorder in the United States. Patients with SCD are at increased risk of invasive pneumococcal disease and are reliant on both early penicillin prophylaxis and antipneumococcal vaccination for prevention of infection. Although studies examining vaccine response have demonstrated a drop-off of titer response after 3 years, an optimal vaccination regimen has not been identified. Our study sought to assess the immunogenicity of our center's pneumococcal vaccination strategy, which included Prevnar (PCV-7) (before the introduction of PCV-13) followed by Pneumovax (PPV-23) given routinely at 2 and 5 years of age and then every 5 years thereafter. Our goal was to assess vaccine response in a population of patients with SCD who had received vaccines according to this regimen using multiplex bead analysis. Our study demonstrated a significant percentage of persons with SCD do not maintain a sufficient vaccination response to PPV-23 for 5 years. Our study revealed that only 36% of patients had protective levels of antipneumococcal antibody titers at an average of 37 months after vaccination. Most alarmingly, within the group of patients with subtherapeutic titers, 64% demonstrated vaccine response to <25% of the tested serotypes. These findings were significantly associated with duration of time since last vaccine administration, but the mean age of lack of response was below the 3-year window where vaccine response was previously reported to wane. Our results indicate antipneumococcal immunity may not be optimally maintained using this vaccination strategy in patients with SCD leaving them vulnerable to invasive pneumococcal disease. Many pediatric hematologists stop prophylactic penicillin at 5 years of age making these results alarming. We recommend further investigation into an optimal vaccine schedule and monitoring of antipneumococcal titers in at-risk patients.

Pneumococcal infections and adult with risk factors

Streptococcus pneumoniae is an important bacterium in humans, and is a cause of upper and lower respiratory tract infections, meningitis, bacteremia, and/or invasive infections. An analysis of literature allows identifying the main risk factors; spleen dysfunctions, sickle cell anemia, alcohol abuse, chronic liver disease, cirrhosis, ischemic cardiac diseases, congestive cardiac failure, diabetes mellitus, obesity, chronic lung disease, immunodeficient patients including HIV infection, and old age. S. pneumoniae infections are more frequent and more severe in these patients. The pathophysiological mechanisms involved may be associated. These populations at risk should receive anti-pneumococcal vaccination. The availability of a 13 valent conjugate vaccine for adult opens new perspectives, but its clinical effectiveness needs to be proved for these patients at risk.

Demand for pneumococcal vaccination under subsidy program for the elderly in Japan

Background

Vaccination programs often organize subsidies and public relations in order to obtain high uptake rates and coverage. However, effects of subsidies and public relations have not been studied well in the literature. In this study, the demand function of pneumococcal vaccination among the elderly in Japan is estimated, incorporating effects of public relations and subsidy.

Methods

Using a data from a questionnaire survey sent to municipalities, the varying and constant elasticity models were applied to estimate the demand function. The response variable is the uptake rate. Explanatory variables are: subsidy supported shot price, operating years of the program, target population size for vaccination, shot location intensity, income and various public relations tools. The best model is selected by c-AIC, and varying and constant price elasticities are calculated from estimation results.

Results

The vaccine uptake rate and the shot price have a negative relation. From the results of varying price elasticity, the demand for vaccination is elastic at municipalities with a shot price higher than 3,708 JPY (35.7 USD). Effects of public relations on the uptake rate are not found.

Conclusions

It can be suggested that municipalities with a shot price higher than 3,708 JPY (35.7 USD) could subsidize more and reduce price to increase the demand for vaccination. Effects of public relations are not confirmed in this study, probably due to measurement errors of variables used for public relations, and studies at micro level exploring individual’s response to public relations would be required.