Who's calling the shots? Pediatricians' adherence to the 2001-2003 pneumococcal conjugate vaccine-shortage recommendations

BACKGROUND

A national shortage of heptavalent pneumococcal conjugate vaccine (PCV7) occurred from September 2001 through May 2003. In December 2001 and January 2002, the Advisory Committee on Immunization Practices and the American Academy of Pediatrics (AAP) issued PCV7-shortage recommendations, emphasizing that all health care providers decrease the number of doses for healthy children so that more children could receive some PCV7.

OBJECTIVES

We assessed (1) how the PCV7 shortage affected pediatricians, (2) whether children in the public and private sectors were vaccinated differently during the shortage, (3) pediatricians' knowledge of and adherence to the Advisory Committee on Immunization Practices/AAP recommendations, (4) and what factors were associated with nonadherence to the recommendations.

METHODS

We conducted a cross-sectional mail survey of 2500 US physician-members of the AAP from November 2002 through March 2003; physicians providing childhood immunizations were eligible. We asked about PCV7-shortage experience, assessed recommendation adherence through clinical scenarios, and modeled potential factors associated with reported nonadherence to the recommendation to defer the fourth PCV7 dose.

RESULTS

Of 2478 surveys sent to valid addresses, 1412 (57%) completed surveys were received; 946 (67%) of these were from eligible pediatricians. Overall, 79% experienced a PCV7 shortage, 94% reported being aware of the recommendations, and 42% reported barriers to recommendation adherence. Ninety-four percent reported vaccinating 6-month-old infants with private or public insurance in the same manner. As recommended, 91% reported fully vaccinating high-risk patients. Contrary to recommendations, 49% reported sometimes or always administering the fourth PCV7 dose to healthy children 12 to 15 months old; their reasons included recurrent otitis media, childcare attendance, and parental desire. Controlling for other characteristics, pediatricians who had no PCV7 shortage in their practices were significantly more likely to report administering the fourth dose than pediatricians who had a shortage (odds ratio [OR]: 3.67; 95% confidence interval [CI]: 2.40-5.63). Other factors associated with nonadherence were being in solo private practice (OR: 2.18; 95% CI: 1.26-3.77) or being male (OR: 1.51; 95% CI: 1.08-2.12). Among pediatricians deferring PCV7, 36% reported having no system to track children for whom PCV7 was deferred.

CONCLUSIONS

Many pediatricians, both with and without a PCV7 shortage, administered more PCV7 doses than recommended. Pediatricians without a shortage were less likely to limit use, which suggests that they might have focused on the perceived value of administering the full schedule to their patients in preference to broader public health goals. Providing more information to physicians on the effectiveness of a fewer-dose schedule and the risk of disease when vaccine is deferred and educating parents might increase adherence to recommendations and achieve more equitable coverage during vaccine shortages.

Pertussis in adolescents and adults: should we vaccinate?

BACKGROUND

The incidence of reported pertussis among adolescents, adults, and young infants has increased sharply over the past decade. Combined acellular pertussis vaccines for adolescents and adults are available in Canada, Australia, and Germany and may soon be considered for use in the United States.

OBJECTIVE

To evaluate the potential health benefits, risks, and costs of a national pertussis vaccination program for adolescents and/or adults.

DESIGN, SETTING, AND POPULATION

The projected health states and immunity levels associated with pertussis disease and vaccination were simulated with a Markov model. The following strategies were examined from the health care payer and societal perspectives: (1) no vaccination; (2) 1-time adolescent vaccination; (3) 1-time adult vaccination; (4) adult vaccination with boosters; (5) adolescent and adult vaccination with boosters; and (6) postpartum vaccination. Data on disease incidence, costs, outcomes, vaccine efficacy, and adverse events were based on published studies, recent unpublished clinical trials, and expert panel input.

MAIN OUTCOME MEASURES

Cases prevented, adverse events, costs (in 2004 US dollars), cost per case prevented, and cost per quality-adjusted life-year (QALY) saved.

RESULTS

One-time adolescent vaccination would prevent 30800 cases of pertussis (36% of projected cases) and would result in 91000 vaccine adverse events (67% local reactions). If pertussis vaccination cost $15 and vaccine coverage was 76%, then 1-time adolescent vaccination would cost $1100 per case prevented (or $1200 per case prevented) or $20000 per QALY (or $23000 per QALY) saved, from the societal (or health care payer) perspective. With a threshold of $50000 per QALY saved, the adolescent and adult vaccination with boosters strategy became potentially cost-effective from the societal perspective only if 2 conditions were met simultaneously, ie, (1) the disease incidence for adolescents and adults was > or =6 times higher than base-case assumptions and (2) the cost of vaccination was less than $10. Adult vaccination strategies were more costly and less effective than adolescent vaccination strategies. The results were sensitive to assumptions about disease incidence, vaccine efficacy, frequency of vaccine adverse events, and vaccine costs.

CONCLUSIONS

Routine pertussis vaccination of adolescents results in net health benefits and may be relatively cost-effective.

Societal Costs and Morbidity of Pertussis in Adolescents and Adults

BACKGROUND

Since the 1980s, the reported incidence of pertussis among adolescents and adults has been steadily increasing. To understand whether the benefits of an acellular pertussis vaccine formulated for adolescents and adults might offset its costs, policy makers will need information about morbidity and societal (medical and nonmedical) costs of pertussis.

METHODS

Adolescents (age, 10-17 years) and adults (age, >or=18 years) with confirmed pertussis illness were identified by the Massachusetts enhanced pertussis surveillance system. We evaluated medical costs in a cohort of patients who had confirmed pertussis during the period of January 1998 through December 2000; nonmedical costs, by means of prospective interviews, in a cohort of patients who had confirmed pertussis during the period of December 2001 through January 2003; and morbidity in both cohorts. Our main outcome measures were mean costs per case, in 2002 US dollars.

RESULTS

In the analysis of medical costs, 1679 adolescents and 936 adults were found to have mean costs of 242 dollars and 326 dollars, respectively (P<.05). In interviews with 314 adolescents and 203 adults, adults had significantly higher nonmedical costs (447 dollars) than those of adolescents (155 dollars). A total of 83% of adolescents missed a mean of 5.5 days from school (range, 0.4-32 days), and 61% of adults missed a mean of 9.8 days from work (range, 0.1-180 days) because of pertussis. Thirty-eight percent of adolescents and 61% of adults were still coughing at the time of the interview, which occurred an average of 106 days and 94 days, respectively, after cough onset.

CONCLUSIONS

Pertussis causes significant morbidity in and costs for adolescents and adults, with time losses comprising the largest proportion of the cost. Societal costs should be considered when making decisions about potential vaccine use in the future.

Ensuring Preparedness for Potential Poliomyelitis Outbreaks

Paralytic poliomyelitis was once endemic in the United States; however, because of high vaccination levels, the last case of wild disease occurred in 1979. Although worldwide polio eradication may be achieved in the near future, the presence of undervaccinated children in urban areas and among groups who refuse vaccination creates an outbreak risk, should importation of wild virus occur. In 1999, the Advisory Committee on Immunization Practices (ACIP) recommended that inactivated poliovirus vaccine (IPV) be used for routine immunization of the US population and that oral poliovirus vaccine (OPV) be reserved for "mass vaccination campaigns to control outbreaks of paralytic polio." Subsequently, the sole US manufacturer of OPV withdrew from the market. In 2003, a joint National Vaccine Advisory Committee (NVAC)/ACIP working group was charged with reporting to its parent bodies concerning the need for a poliovirus vaccine stockpile. Based on that working group's report, the NVAC and ACIP have concluded that stockpiles of both IPV and OPV should be maintained. In the event of an outbreak in which OPV continues not to be available, IPV should be used for control, and a stockpile of 8 million doses seems to be sufficient. Should IPV be manufactured only in combination with other vaccines, appropriate procurement actions should be taken to ensure that uncombined IPV continues to be stockpiled. Under circumstances of diminished population immunity, OPV may offer outbreak control advantages. The NVAC and ACIP recommend that the United States collaborate with international agencies to provide guaranteed and rapid access to at least 8 million doses of trivalent OPV or 8 million doses of each of the 3 types of monovalent OPV. The regulatory and practical obstacles to implementation of this recommendation will require assertive facilitation at high levels of the federal government and careful planning at the state and local levels.

Novel non-mecA-containing staphylococcal chromosomal cassette composite island containing pbp4 and tagF genes in a commensal staphylococcal species: a possible reservoir for antibiotic resistance islands in Staphylococcus aureus

Among methicillin-resistant Staphylococcus aureus isolates, a staphylococcal chromosomal cassette containing the mecA gene (SCCmec) is integrated into the chromosome at a unique site. SCCmec also contains unique ccrAB recombinase genes mediating its integration and excision from the genome and is flanked by characteristic left and right direct- and inverted-repeat sequences. A few non-mecA-containing SCC elements that have the other molecular features described above have recently been described. The origin of these cassettes is not clear. We have identified two new members of the SCC family integrated within orfX in Staphylococcus epidermidis strain ATCC 12228, neither of which carries mecA. One is a 57-kb element flanked by a unique 28-bp SCC direct repeat. It was called the SCC composite island (SCC-CI) because it carries a 19-kb SCC element (SCCpbp4) nested within it. SCCpbp4 contains pbp4 and tagF genes, as well as one pair of ccrAB genes (allotype 2) flanked by classical SCC-specific terminal repeats. External to SCCpbp4, SCC-CI contains a second pair of ccrAB genes (allotype 4), three IS431 elements, and genes mediating resistance to heavy metals. Genes mediating restriction-modification that may facilitate horizontal transfer are also present within SCC-CI, both within and outside SCCpbp4. Several novel arrangements of the SCC direct and inverted repeats were identified. Several long stretches of homology with other SCCs were found within and outside SCCpbp4. In view of the fact that SCC-CI was found in a commensal species, it may represent a reservoir for sequences involved in genetic shuffling between staphylococci and may contribute to the diversity found in SCC elements.

Trends in pertussis among infants in the United States, 1980-1999

CONTEXT

Reported cases of pertussis among adolescents and adults have increased since the 1980s, despite increasingly high rates of vaccination among infants and children. However, severe pertussis morbidity and mortality occur primarily among infants.

OBJECTIVE

To describe the trends and characteristics of reported cases of pertussis among infants younger than 12 months in the United States from 1980 to 1999.

DESIGN, SETTING, AND PARTICIPANTS

Cases of pertussis in infants younger than 12 months in the United States reported to the National Notifiable Disease Surveillance System of the Centers for Disease Control and Prevention between 1980 and 1999, and detailed case data from the Supplementary Pertussis Surveillance System.

MAIN OUTCOME MEASURES

Incidence and demographic and clinical characteristics of cases.

RESULTS

The incidence of reported cases of pertussis among infants increased 49% in the 1990s compared with the incidence in the 1980s (19 798 vs 12 550 cases reported; 51.1 cases vs 34.2 cases per 100 000 infant population, respectively). Increases in the incidence of cases and the number of deaths among infants during the 1990s primarily were among those aged 4 months or younger, contrasting with a stable incidence of cases among infants aged 5 months or older. The proportion of cases confirmed by bacterial culture was higher in the 1990s than in the 1980s (50% and 33%, respectively); the proportion of hospitalized cases was unchanged (67% vs 68%, respectively). Receipt of fewer doses of vaccine was associated with hospitalization, when cases were stratified by age in months.

CONCLUSIONS

The incidence of reported cases of pertussis among infants increased in the 1990s compared with the 1980s. The limited age group affected, the increased rate of bacteriologic confirmation, and the unchanged severity of illness suggest that an increase in infant pertussis has occurred apart from any change in reporting. Strategies are needed to prevent the morbidity and mortality from pertussis among infants too young to be fully vaccinated, according to the current recommended schedules of vaccination in the United States.

Increase in deaths from pertussis among young infants in the United States in the 1990s

BACKGROUND

Severe pertussis primarily occurs among infants (<12 months of age). Despite high levels of immunization, reported pertussis cases increased in the United States in the 1990s among all age groups, including infants.

METHODS

To characterize fatal pertussis cases, we analyzed pertussis deaths reported to CDC in the 1990s and compared these with data on pertussis deaths reported in the 1980s. Data from national surveillance systems and from available medical records were used, including data from analyses of deaths reported in 1992 through 1995.

RESULTS

In 1980 through 1989, 77 pertussis deaths were reported; 61 deaths were among infants (1.67 deaths per million), including 49 among infants <4 months of age. In the 1990s 103 pertussis deaths were reported; 93 deaths were among infants (2.40 deaths per million), including 84 among infants <4 months of age. Of 89 infants with ethnicity data, 31 (36%) were Hispanic; the mortality rate among Hispanic infants (4.77 per million) was higher than among non-Hispanic infants (1.80 per million). Of 76 infants with reported gestational age, 40 (53%) were born at <37 weeks, including 22 (29%) who were born at <35 weeks. Severe pulmonary hypertension was a common lethal complication among infants.

CONCLUSIONS

Pertussis deaths increased among infants too young to be protected by immunization. A disproportionate share of deaths were complicated by pulmonary hypertension and occurred among Hispanic infants and infants born at <37 weeks gestation. New approaches to prevent infection among infants <4 months of age and improved therapies for pertussis complications are needed.

Tetanus surveillance--United States, 1998--2000

PROBLEM/CONDITION

Tetanus is a severe and often fatal infection. The incidence of reported cases in the United States has declined steadily since introduction of tetanus toxoid vaccines in the 1940s.

REPORTING PERIOD

This report covers surveillance data for 1998--2000.

DESCRIPTION OF SYSTEM

Physician-diagnosed cases of tetanus were reported to CDC's National Notifiable Disease Surveillance System. Supplemental clinical and epidemiologic information were provided by states.

RESULTS AND INTERPRETATION

During 1998--2000, an average of 43 cases of tetanus was reported annually; the average annual incidence was 0.16 cases/million population. The highest average annual incidence of reported tetanus was among persons aged >60 years (0.35 cases/million population), persons of Hispanic ethnicity (0.37 cases/million population), and older adults known to have diabetes (0.70 cases/million population). Fifteen percent of the cases were among injection-drug users. The case-fatality ratio was 18% among 113 patients with known outcome; 75% of the deaths were among patients aged >60 years. No deaths occurred among those who were up-to-date with tetanus toxoid vaccination. Seventy-three percent of 129 cases with known injury information available reported an acute injury; of these, only 37% sought medical care for the acute injury, and only 63% of those eligible received tetanus toxoid for wound prophylaxis.

INTERPRETATION

The majority of tetanus cases occurred among persons inadequately vaccinated or with unknown vaccination history who sustained an acute injury. Adults aged >60 years were at highest risk for tetanus and tetanus-related death.

PUBLIC HEALTH ACTIONS

Tetanus is preventable through routine vaccination (i.e., primary series and decennial boosters) and appropriate management. A shortage of tetanus and diphtheria toxoids vaccine that began during 2000 ended in 2002. Efforts by health-care providers are warranted to vaccinate persons with delayed or incomplete vaccination, with emphasis on older persons and persons with high-risk conditions.

The first oral rotavirus vaccine, 1998-1999: estimates of uptake from the National Immunization Survey

OBJECTIVE

On August 31, 1998, the rhesus-human reassortant rotavirus vaccine (RRV-TV) was licensed for use in the U.S. During the next nine months, 15 cases of intussusception were reported among infants who received the vaccine. Case-control and cohort studies showed a significantly increased risk of developing intussusception within one week of receiving the vaccine; subsequent ecologic studies did not. In this study, the authors used data on RRV-TV vaccination rates from the National Immunization Survey (NIS) to estimate state and national RRV-TV uptake rates and factors associated with receiving RRV-TV. These estimates are a key component in evaluating published ecologic studies designed to investigate the relationship between receipt of the vaccine and intussusception.

METHODS

The authors analyzed NIS data for children ages 19 to 35 months who were eligible to receive RRV-TV between September 1998 and July 1999. The authors estimated vaccine coverage and the number of doses administered by state, NIS sampling quarter, and birth cohort, and analyzed demographic and socioeconomic variables to evaluate their relationship with receiving RRV-TV.

RESULTS

It was estimated that approximately 1 million doses of RRV-TV were administered to 504,585 (+/-61,854) children, 13.4% (+/-1.6%) of children who were eligible. The estimated number of doses administered and the vaccination coverage rate varied greatly from state to state. Children living in households with higher socioeconomic conditions were more likely to receive the vaccine.

CONCLUSION

Ecologic studies had a limited ability to detect a significant increase in the population incidence rate of intussusception that could be attributed to RRV-TV because populations in these studies consisted primarily of children who did not receive the vaccine. The example from RRV-TV demonstrates some of the challenges of assessing the magnitude of the association between a vaccine and an uncommon or rare adverse event.

Impact of universal Haemophilus influenzae type b vaccination starting at 2 months of age in the United States: an economic analysis

OBJECTIVE

To evaluate the economic impact of universal Haemophilus influenzae type b (Hib) vaccination starting at 2 months of age.

METHODS

Decision-tree-based analysis was conducted of a hypothetical US birth cohort of 3 815 469 infants using population-based vaccination coverage and disease incidence data. All costs were estimated from both the direct cost (medical and nonmedical) and societal perspectives. Net present value, cost-effectiveness ratios, and benefit-cost ratios of the US Hib vaccination program were evaluated.

RESULTS

The results of these analyses showed that the universal vaccination program using the Hib conjugate vaccines in the United States in 2000 was cost-saving from both the direct and societal perspectives, with the benefit of the Hib vaccination program (net present value) from the direct cost and societal perspectives of $0.95 billion and $2.09 billion, respectively. Without a Hib vaccination program, the direct and societal costs of Hib invasive cases would be $1.35 billion and $2.58 billion, respectively. The direct and societal costs of the Hib vaccination program were estimated at $0.39 billion and $0.48 billion, respectively. The direct and societal benefit-cost ratios for the Hib vaccination program were 3.4 and 5.4, respectively. Varying the proportion of vaccines purchased and administered in the public versus the private sector and the proportion of combination vaccine versus monovalent vaccine administered did not have much effect on the results.

CONCLUSIONS

Regardless of the perspective (direct cost or societal) and the assumptions used, the benefit-cost ratios of the US vaccination program are >1.0. Potential changes in the program, including use of more or less Hib combination vaccines, would not significantly alter the benefit-cost ratio. The national Hib vaccination program is highly cost beneficial and results in substantial cost savings.

Philosophic objection to vaccination as a risk for tetanus among children younger than 15 years

OBJECTIVES

Although safe and effective vaccines are available to protect against tetanus in the United States and vaccination rates are high, cases of tetanus among children continue to occur. The objectives of this article are to describe reported cases of tetanus in children in the United States and to identify the reasons for lack of protection against tetanus.

METHODS

We reviewed all cases of tetanus in children <15 years of age that were reported to the National Notifiable Diseases Surveillance System from 1992 through 2000. Cases were defined by physician diagnosis. We verified the information in the case reports with state and local health departments.

RESULTS

From 1992 through 2000, 15 cases of tetanus in children <15 years of age were reported from 11 states. Twelve cases were in boys. Two cases were in neonates <10 days of age; the other 13 cases were in children who ranged in age from 3 to 14 years. The median length of hospitalization was 28 days; 8 children required mechanical ventilation. There were no deaths. Twelve (80%) children were unprotected because of lack of vaccination, including 1 neonate whose mother was not vaccinated. Among all unvaccinated cases, objection to vaccination, either religious or philosophic, was the reported reason for choosing not to vaccinate.

CONCLUSION

The majority of recent cases of tetanus among children in the United States were in unvaccinated children whose parents objected to vaccination. Parents who choose not to vaccinate their children should be advised of the seriousness of the disease and be informed that tetanus is not preventable by means other than vaccination.

Tyrosine phosphorylation following alterations in arteriolar intraluminal pressure and wall tension

Arterioles respond to increased transmural pressure with myogenic constriction. The present study investigated the role of tyrosine phosphorylation in myogenic activity. Cannulated segments of a rat cremaster arteriole were fixed under pressure, followed by incubation with fluorescein isothiocyanate (FITC)-conjugated anti-phosphotyrosine. Smooth muscle cell fluorescence intensity was measured with the use of confocal laser-scanning microscopy. Anti-phosphotyrosine fluorescence intensity in muscle cells of arterioles maintained at 100 mmHg was reduced by the tyrosine kinase inhibitor tyrphostin A47 (30 microM) and increased by the tyrosine phosphatase inhibitor pervanadate (100 microM). In time-course experiments, anti-phosphotyrosine fluorescence increased slowly (over 5 min) after an acute increase in intraluminal pressure, and was dissociated from myogenic contraction (within 1 min). In contrast, angiotensin II (0.1 microM) caused rapid constriction and increased tyrosine phosphorylation. Anti-phosphotyrosine fluorescence was also pressure dependent (10-100 mmHg). Abolition of myogenic activity, either through removal of extracellular Ca2+, or exposure to verapamil (5 microM) or forskolin (0.1 microM) caused a further increase in anti-phosphotyrosine fluorescence. We conclude that transmural pressure and/or wall tension in arterioles causes increased tyrosine phosphorylation; however, this is not involved in the acute phase of myogenic constriction but may be involved in later responses, such as sustained myogenic tone or mechanisms possibly related to growth.

Intussusception among infants given an oral rotavirus vaccine

BACKGROUND

Intussusception is a form of intestinal obstruction in which a segment of the bowel prolapses into a more distal segment. Our investigation began on May 27, 1999, after nine cases of infants who had intussusception after receiving the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) were reported to the Vaccine Adverse Event Reporting System.

METHODS

In 19 states, we assessed the potential association between RRV-TV and intussusception among infants at least 1 but less than 12 months old. Infants hospitalized between November 1, 1998, and June 30, 1999, were identified by systematic reviews of medical and radiologic records. Each infant with intussusception was matched according to age with four healthy control infants who had been born at the same hospital as the infant with intussusception. Information on vaccinations was verified by the provider.

RESULTS

Data were analyzed for 429 infants with intussusception and 1763 matched controls in a case-control analysis as well as for 432 infants with intussusception in a case-series analysis. Seventy-four of the 429 infants with intussusception (17.2 percent) and 226 of the 1763 controls (12.8 percent) had received RRV-TV (P=0.02). An increased risk of intussusception 3 to 14 days after the first dose of RRV-TV was found in the case-control analysis (adjusted odds ratio, 21.7; 95 percent confidence interval, 9.6 to 48.9). In the case-series analysis, the incidence-rate ratio was 29.4 (95 percent confidence interval, 16.1 to 53.6) for days 3 through 14 after a first dose. There was also an increase in the risk of intussusception after the second dose of the vaccine, but it was smaller than the increase in risk after the first dose. Assuming full implementation of a national program of vaccination with RRV-TV, we estimated that 1 case of intussusception attributable to the vaccine would occur for every 4670 to 9474 infants vaccinated.

CONCLUSIONS

The strong association between vaccination with RRV-TV and intussusception among otherwise healthy infants supports the existence of a causal relation. Rotavirus vaccines with an improved safety profile are urgently needed.

Poliomyelitis prevention in the United States. Updated recommendations of the Advisory Committee on Immunization Practices (ACIP)

These recommendations of the Advisory Committee on Immunization Practices (ACIP) for poliomyelitis prevention replace those issued in 1997. As of January 1, 2000, ACIP recommends exclusive use of inactivated poliovirus vaccine (IPV) for routine childhood polio vaccination in the United States. All children should receive four doses of IPV at ages 2, 4, and 6-18 months and 4-6 years. Oral poliovirus vaccine (OPV) should be used only in certain circumstances, which are detailed in these recommendations. Since 1979, the only indigenous cases of polio reported in the United States have been associated with the use of the live OPV. Until recently, the benefits of OPV use (i.e., intestinal immunity, secondary spread) outweighed the risk for vaccine-associated paralytic poliomyelitis (VAPP) (i.e., one case among 2.4 million vaccine doses distributed). In 1997, to decrease the risk for VAPP but maintain the benefits of OPV, ACIP recommended replacing the all-OPV schedule with a sequential schedule of IPV followed by OPV. Since 1997, the global polio eradication initiative has progressed rapidly, and the likelihood of poliovirus importation into the United States has decreased substantially. In addition, the sequential schedule has been well accepted. No declines in childhood immunization coverage were observed, despite the need for additional injections. On the basis of these data, ACIP recommended on June 17, 1999, an all-IPV schedule for routine childhood polio vaccination in the United States to eliminate the risk for VAPP. ACIP reaffirms its support for the global polio eradication initiative and the use of OPV as the only vaccine recommended to eradicate polio from the remaining countries where polio is endemic.

Meningococcal disease in Dallas County, Texas: results of a six-year population-based study

OBJECTIVE

Neisseria meningitidis is an important cause of serious bacterial infection in children and adults in the US. From 1992 to 1997 invasive disease caused by N. meningitidis was studied among 1.9 million residents of Dallas County, TX METHODS: The demographic characteristics and diagnoses of 151 patients were identified through active, population-based surveillance and review of medical records. Serogroups were determined for strains infecting 129 (85%) patients.

RESULTS

The average annualized incidence rate was 1.3 cases per 100,000 person years and was highest for children <1 year (13 cases/100,000 person years). Older patients (50+ years old) were more likely to present with pneumonia and less likely to present with meningitis than younger patients. Neither the fatality rate nor the duration of hospitalization for surviving patients was associated with age. Among patients with a known serogroup, serogroup C disease was found in 35% of cases <1 year old, 64% of those 1 to 49 years old and 44% of those 50+ years old. Serogroup B strains were isolated from 26% of patients <1 year, 17% of patients 1 to 49 years old and none of the patients 50+ years old. Serogroup Y disease increased from 22% to 35% of cases between 1992 and 1997 (P = 0.03). This serogroup was identified in 26% of patients <1 year old, 17% of patients 1 to 49 years old and in 50% of patients 50+ years old. Serogroup C and Y accounted for 61% of cases in children <1 year old and for 79% of cases in all age groups.

CONCLUSION

The results underscore the importance of conjugate vaccines for serogroups C and Y.

Tyrosine phosphorylation modulates arteriolar tone but is not fundamental to myogenic response

The present study investigated the role of protein tyrosine phosphorylation in myogenic responsiveness of rat skeletal muscle arterioles. Arteriolar segments were cannulated and pressurized without intraluminal flow. All vessels studied developed spontaneous tone and demonstrated significant myogenic constriction to step changes in pressure with a resultant increase in myogenic tone over an intraluminal pressure range of 50-150 mmHg. Step increases in intraluminal pressure from 50 to 120 mmHg caused a rapid and sustained elevation in intracellular [Ca(2+)], as measured using fura 2. Vessels with myogenic tone dilated in response to tyrosine kinase inhibitors genistein (10 or 30 microM) and tyrphostin A47 (10 or 30 microM) and constricted to the tyrosine phosphatase inhibitor pervanadate (1 or 10 microM). Despite the dilator effect, myogenic reactivity was not blocked by the inhibitors. Daidzein (10 microM), a compound structurally similar to genistein but without tyrosine kinase-inhibiting activity, did not alter vessel tone or myogenic responses. Preincubation of arterioles with genistein or tyrphostin A47 did not significantly alter baseline arteriolar [Ca(2+)], and neither drug reduced the increase in [Ca(2+)] following an acute increase in intraluminal pressure. Constriction induced by pervanadate (10 microM) was not accompanied by a significant increase in intracellular [Ca(2+)], even though removal of extracellular Ca(2+) reversed the constriction. Examination of smooth muscle tyrosine phosphorylation, using a fluorescent phosphotyrosine antibody and confocal microscopy, showed that increased intraluminal pressure resulted in an increase in anti-phosphotyrosine fluorescence. Because manipulation of tyrosine kinase activity was found to alter vessel diameter, these data support a role for tyrosine phosphorylation in modulation of arteriolar tone. However, the results indicate that acute arteriolar myogenic constriction does not require tyrosine phosphorylation.

Structural determinants of phorbol ester binding in synaptosomes: pharmacokinetics and pharmacodynamics

The present study used structurally distinct phorbol esters to investigate the relationship between their pharmacokinetics of binding to protein kinase C (PKC) in rat brain cortex synaptosomes, their affinity for PKC in synaptosomes and ability to enhance noradrenaline release from rat brain cortex. Affinity binding studies using [3deoxyphorbol 13-tetradecanoate (dPT)=PDB&z. Gt;12-deoxyphorbol 13-acetate (dPA)=phorbol 12,13-diacetate (PDA). In intact synaptosomes PDB, dPA and PDA rapidly displaced bound [3H]PDB whereas PMA and dPT were comparatively slow. However, the displacement rates for all the phorbol esters were equally rapid in synaptosomal membranes or synaptosomes permeabilised with Staphylococcus alpha-toxin. These results suggest that the lipophilic phorbol esters (dPT and PMA) are slower to displace [3H]PDB binding because they are hindered by the plasma membrane. In brain cortex slices it was found that the rate of displacement of [3H]PDB binding was closely correlated with the degree of elevation of transmitter noradrenaline release. Thus kinetic characteristics may determine biological responses and this may be particularly evident in events which occur rapidly or where there is fast counter-regulation.

Methicillin-resistant Staphylococcus aureus in two child care centers

Methicillin-resistant Staphylococcus aureus (MRSA) has not been studied in child care centers. The prevalence of MRSA colonization was determined at two centers with an index patient. Two (3%) of 61 children at center X had MRSA; strains from both children and the index illness were pulsed-field gel electrophoresis type B. Nine (24%) of 40 children at center Y had MRSA; strains from 5 children and the index illness were type B, and strains from 4 children were type A. Ten of 11 colonized children were in classes with 2- and 3-year-old children. Colonization with MRSA was not associated with health care contact by subjects or by members of their households. MRSA in child day care centers indicates accelerated spread of MRSA in the community.

Invasive pneumococcal disease in Dallas County, Texas: results from population-based surveillance in 1995

We studied the epidemiology of invasive disease caused by Streptococcus pneumoniae in 1995 among 1.9 million residents of Dallas County, Texas. The sociodemographic characteristics and chronic medical conditions of 432 patients were identified through active, population-based surveillance and review of medical records. The incidence of disease was 22 cases per 100,000 person-years and was highest for children < 2 years of age (136 cases per 100,000 person-years) and for adults > or = 65 years of age (80 cases per 100,000 person-years). Twenty percent of isolates were nonsusceptible to penicillin; the highest rates of resistance were among the youngest and oldest age groups (28% and 22% of isolates, respectively). An increased incidence of disease was associated with low income (42 cases per 100,000 person-years) and black race (39 cases per 100,000 person-years). The frequency of most chronic medical conditions increased with age; smoking, heavy alcohol use, and infection due to human immunodeficiency virus were most common between 30 and 64 years of age. Of otherwise healthy patients 30-64 years of age, 47% were current smokers, an association requiring further investigation. Characterizing groups at risk for invasive pneumococcal disease could aid in the development of prevention programs and increase the benefits from wide use of effective vaccines.

17Beta-oestradiol enhances nitric oxide synthase activity in endothelium-denuded rat aorta

1. It has been suggested that oestrogen-produced vasodilatation is due to induction of endothelial nitric oxide synthase (NOS), but there are many reports of direct effects on vascular smooth muscle. In the present study, these processes were investigated in rat aorta isolated from ovariectomized rats. 2. Short-term treatment (10 min) with 17beta-oestradiol (10 micromol/L) produced a small attenuation of the phenylephrine (PE)-induced constriction, which was unaffected by the nitric oxide synthase inhibitor L-N5(-1-iminoethyl)ornithine (NIO; 100 micromol/L). Long-term treatment (6 h) with 17beta-oestradiol (10 micromol/L) did not affect acetylcholine-mediated vasorelaxation in endothelium-intact aortic rings, but did attenuate PE-induced constriction. This attenuation was also observed in endothelium-denuded preparations after 17beta-oestradiol (10 micromol/L for 6 h) and was far greater than the acute effect of 17beta-oestradiol (10 micromol/L). 3. The attenuation produced by 17beta-oestradiol (10 micromol/L for 6 h) was significantly inhibited by concomitant treatment with cycloheximide (1 micromol/L), suggesting that protein synthesis was involved. NIO (100 micromol/L) also attenuated the effect, which suggests that the anti-constrictor effect of 17beta-oestradiol occurs through the increased production of nitric oxide (NO). 17Beta-oestradiol increased NO production, as assessed by the conversion of [3H]-arginine to [3H]-citrulline in rat aorta. These effects were prevented by cycloheximide and NIO. The anti-constrictor effect of oestrogen was blocked by the oestrogen receptor antagonist ICI 182 780 (100 nmol/L). 4. Western blotting using an antibody specific for inducible nitric oxide synthase (NOS) revealed that 17beta-oestradiol (10 micromol/L for 24 h) treatment induced the formation of inducible NOS protein in the aorta, an effect blocked by cycloheximide. The results indicate that 17beta-oestradiol can attenuate the vasoconstrictor effect of PE by a specific receptor-mediated process that involves induction of inducible NOS.