Pediatricians' adherence to pneumococcal conjugate vaccine shortage recommendations in 2 national shortages

Understanding the relationship between stay-at-home measures and vaccine shortages: a conventional, heterogeneous, and fractional dynamic approach

In light of the global prevalence of a highly contagious respiratory disease, this study presents a novel approach to address the pressing and unanticipated issues by introducing a modified vaccination and lockdown-centered epidemic model. The rapid spread of the disease is attributed to viral transmissibility, the emergence of new strains (variants), lack of immunization, and human unawareness. This study aims to provide policymakers with crucial insights for making informed decisions regarding lockdown strategies, vaccine availability, and other control measures. The research adopts three types of models: deterministic, heterogeneous, and fractional-order dynamics, on both theoretical and numerical approaches. The heterogeneous network considers varying connectivity and interaction patterns among individuals, while the ABC fractional-order derivatives analyze the impact of integer-order control in different semi-groups. An extensive theoretical analysis is conducted to validate the proposed model. A comprehensive numerical investigation encompasses deterministic, stochastic, and ABC fractional-order derivatives, considering the combined effects of an effective vaccination program and non-pharmaceutical interventions, such as lockdowns and shutdowns. The findings of this research are expected to be valuable for policymakers in different countries, helping them implement dynamic strategies to control and eradicate the epidemic effectively.

Effects of a nationwide Hib vaccine shortage on vaccination coverage in the United States

BACKGROUND

A shortage of Haemophilus influenzae type b (Hib) vaccine that occurred in the United States during December 2007 to September 2009 resulted in an interim recommendation to defer the booster dose, but to continue to vaccinate as recommended with the primary series during the first year of life.

OBJECTIVES

To quantify effects of the Hib shortage on vaccination coverage and to determine if any demographic subgroups were disproportionately affected.

METHODS

Data from the 2009 National Immunization Survey (NIS) were divided based on child's age at the onset of the shortage. Comparisons were made in primary series coverage by 9 months between children <7 months versus ≥7 months at the start of the shortage. Comparisons in primary series plus booster dose completion by 19 months were made between children who were <12 months versus ≥12 months at the start of the shortage.

RESULTS

Nationally, there was a difference in Hib primary series completion by 9 months among children age <7 months versus ≥7 months at the start of the shortage (73.9% versus 81.2%, P<0.001). There was a large difference in the percentage of children fully vaccinated with the primary series plus booster dose by 19 months among children age <12 months versus ≥12 months at the start of the shortage (39.5% versus 66.0%, P<0.001). There were differential effects of the shortage on primary series coverage among states and for some demographic characteristics.

CONCLUSIONS

As expected booster dose coverage was reduced consistent with interim recommendations, but primary series coverage was also reduced by 7 percentage points nationally.

Up-to-date Haemophilus influenzae type b vaccination coverage during a vaccine shortage

OBJECTIVES

We sought to assess Haemophilus influenzae type b (Hib) vaccination coverage in diverse areas of the United States during the 2008-2009 Hib vaccine shortage. Interim recommendations for Hib vaccination during the shortage called for deferral of the booster dose only among children not at high risk for disease; the primary series given during the first year of life continued to be recommended for all children.

METHODS

Vaccination data on ∼123,000 children were collected from 8 Immunization Information System (IIS) sentinel sites. Completion of the primary Hib series (with 2 or 3 doses depending on vaccine type) by 9 months old during the vaccine shortage was compared with coverage of 2 vaccines given at similar ages (7-valent pneumococcal conjugate vaccine and diphtheria, tetanus acellular pertussis vaccine) in children born between November 1, 2007, and March 31, 2008.

RESULTS

During the shortage period, Hib vaccination coverage for the primary series was 7.8 to 10.3 percentage points lower than diphtheria, tetanus acellular pertussis vaccine and 7-valent pneumococcal conjugate vaccine coverage for children by the age of 9 months in 7 of 8 sentinel sites.

CONCLUSIONS

A significant decrease in Hib vaccination coverage for the primary series was observed and was consistent across several US localities. Close collaboration between the public health community and vaccine providers is essential during vaccine shortages to ensure that interim vaccination recommendations are clear, widely disseminated, and closely followed, and that access to available vaccine supplies is maintained.

Knowledge of interim recommendations and use of Hib vaccine during vaccine shortages

OBJECTIVES

The goals were to determine among pediatricians and family physicians (1) knowledge of interim recommendations regarding Haemophilus influenzae type b (Hib) vaccine administration, (2) current practices, and (3) factors associated with nonadherence.

METHODS

An Internet-based survey was conducted in April 2008 among national samples.

RESULTS

Response rates were 68% (220 of 325 physicians) among pediatricians and 51% (153 of 302 physicians) among family physicians. Seventy-three percent of pediatricians and 45% of family medicine physicians reported insufficient Hib vaccine supplies, and 22% to 24% reported having to defer doses for infants 2 to 6 months of age > or =10% of the time. Ninety-eight percent of pediatricians and 81% of family physicians were aware of the interim recommendations (P < or = .0001), and virtually all knew that the booster dose should be deferred; however, 22% of pediatricians and 33% of family medicine physicians reported not deferring this dose. Physicians in both specialties were less likely to adhere to recommendations to defer in this age group if they thought that their practice had sufficient vaccine supplies (pediatricians, odds ratio: 0.01 [95% confidence interval: 0.003-0.03]; family medicine physicians, odds ratio: 0.10 [95% confidence interval: 0.03-0.33]). Family medicine physicians were less likely to adhere to recommendations if they had not heard about the interim recommendations (odds ratio: 0.04 [95% confidence interval: 0.01-0.21]).

CONCLUSIONS

Most primary care physicians experienced Hib vaccine shortages, and many have had to defer doses for 2- to 6-month-old children. Most are knowledgeable regarding interim recommendations, but one-fifth to one-third reported nonadherence.

Temporary vaccine recommendations and provider compliance: a survey of pediatric practices during the 2003-2004 pneumococcal conjugate vaccine shortage

OBJECTIVE

Heptavalent pneumococcal conjugate vaccine was in short supply from December 2003 to August 2004. The Centers for Disease Control and Prevention with the American Academy of Pediatrics and the American Academy of Family Physicians made recommendations to providers to withhold third and fourth doses of heptavalent pneumococcal conjugate vaccine to ensure availability for those at highest risk. Previous studies of vaccine shortages have demonstrated that provider compliance with temporary recommendations is low. The objective of this study was to collect timely data about awareness and adherence to temporary recommendations and current supply status of heptavalent pneumococcal conjugate vaccine in pediatric practices.

METHODS

A 2-phase telephone survey of pediatric practices was conducted during a 10-week period during the 2003-2004 heptavalent pneumococcal conjugate vaccine shortage. Immunization nurses at randomly selected sites with physician-members of the American Academy of Pediatrics were asked a series of questions.

RESULTS

In both study phases, >90% of participating practices were aware of the recommendations and reported adhering to the recommendations. In phase 1, practices with insufficient supply were more likely to implement recommendations than practices with sufficient supply. Participants identified health departments and Wyeth Vaccines as the most common sources of information. At least 65% of the practices in each phase reported use of tracking systems for children who missed doses.

CONCLUSIONS

Most pediatric practices surveyed were aware of the shortage and were implementing the heptavalent pneumococcal conjugate vaccine recommendations. Simplified recommendations and collaborative efforts to develop and widely disseminate interim recommendations may result in increased compliance by providers.