Stan L. Block

Comparison of the Immunogenicity and Reactogenicity of a Prophylactic Quadrivalent Human Papillomavirus (Types 6, 11, 16, and 18) L1 Virus-Like Particle Vaccine in Male and Female Adolescents and Young Adult Women

OBJECTIVE. Prophylactic vaccination of 16- to 23-year-old females with a quadrivalent human papillomavirus (types 6, 11, 16, 18) L1 virus-like particle vaccine has been shown to prevent type-specific human papillomavirus infection and associated clinical disease. We conducted a noninferiority immunogenicity study to bridge the efficacy findings in young women to preadolescent and adolescent girls and boys, who represent a primary target for human papillomavirus vaccination. METHODS. We enrolled 506 girls and 510 boys (10–15 years of age) and 513 females (16–23 years of age). Participants were vaccinated on day 1, at month 2, and at month 6, and serology testing was performed on day 1 and at months 3 and 7 on blinded samples. Neutralizing antibody concentrations were determined using type-specific immunoassays and summarized as geometric mean titers and seroconversion rates. Vaccine tolerability also was assessed. RESULTS. By month 7, seroconversion rates were ≥99% for all 4 human papillomavirus types in each group. By month 7, compared with women, anti–human papilloma virus geometric mean titers in girls or boys were noninferior and were 1.7- to 2.7-fold higher. Most (>97%) injection-site adverse events were mild to moderate in intensity. Significantly more boys (13.8%) and girls (12.8%) than women (7.3%) reported fevers ≥37.8°C within 5 days of vaccination. Most (96.4%) fevers were mild (<39°C). CONCLUSIONS. Noninferior immunogenic responses to all 4 human papillomavirus types in the quadrivalent vaccine permit the bridging of efficacy data that were generated in young women to girls. The results in boys lend support for the implementation of gender-neutral human papillomavirus vaccination programs. This vaccine generally was well tolerated.

Efficacy of vaccination with live attenuated, cold-adapted, trivalent, intranasal influenza virus vaccine against a variant (A/Sydney) not contained in the vaccine

OBJECTIVE To determine the safety, immunogenicity, and efficacy of revaccination of children with live attenuated influenza vaccine. STUDY DESIGN A 2-year multicenter, double-blind, placebo-controlled, efficacy field trial of live attenuated, cold-adapted trivalent influenza vaccine administered by nasal spray to children. This report summarizes year 2 results, a year in which the epidemic strain of influenza A/Sydney was not well matched to the vaccine strains. Each year, vaccine strains were antigenically equivalent to the contemporary inactivated influenza vaccine. In year 2, a single intranasal revaccination was administered. Active surveillance for influenza was conducted during the influenza season by means of viral cultures. Influenza cases were defined as illnesses with wild-type influenza virus isolated from respiratory secretions. RESULTS In year 2, 1358 (85%) children, 26 to 85 months of age, returned for revaccination. The intranasal vaccine was easily accepted, well tolerated, and immunogenic. Revaccination resulted in 82% to 100% of the vaccinated children in a subset studied for immunogenicity being seropositive as compared with 26% to 65% of placebo recipients, depending on the influenza strain tested. No serious adverse events were associated with the vaccine. In addition to the strains in the vaccine, antibody was induced to the variant strain A/Sydney/H3N2. In year 2, influenza A/Sydney/H3N2, a variant not contained in the vaccine, caused 66 of 70 cases of influenza A; nonetheless, intranasal vaccine was 86% efficacious in preventing A/Sydney influenza. Eight cases of lower respiratory tract disease were associated with A/Sydney influenza; all cases were in the placebo group. CONCLUSIONS This live attenuated, cold-adapted influenza vaccine was safe, immunogenic, and efficacious against influenza A/H3N2 (including a variant, A/Sydney, not contained in the vaccine) and influenza B. The characteristics of this vaccine make it suitable for routine use in children to prevent influenza.

Correlates of Immune Protection Induced by Live, Attenuated, Cold-Adapted, Trivalent, Intranasal Influenza Virus Vaccine

The authors conducted a 2-year, multicenter, double-blind, placebo-controlled efficacy field trial of live, attenuated, cold-adapted, trivalent influenza vaccine administered by nasal spray to children 15-71 months old. Overall, vaccine was 92% efficacious at preventing culture-confirmed infection by influenza A/H3N2 and influenza B. Because influenza A/H1N1 did not cause disease during the years in which this study was conducted, the authors sought to determine vaccine efficacy and correlates of immune protection against experimental challenge with 107 TCID50 of attenuated H1N1 (vaccine strain) by intranasal spray. Prechallenge assessments included serum hemaglutination-inhibiting (HAI) antibody and nasal wash IgA antibody to H1N1. Vaccine was 83% efficacious (95% confidence interval, 60%-93%) at preventing shedding of H1N1 virus after challenge. Any serum HAI antibody or any nasal wash IgA antibody was correlated with significant protection from H1N1 infection as indicated by vaccine-virus shedding, and high efficacy against H1N1 challenge was demonstrated.

Immunogenicity and Safety of 13-Valent Pneumococcal Conjugate Vaccine in Infants and Toddlers

BACKGROUND: 7-Valent pneumococcal conjugate vaccine (PCV7 [Prevnar, Wyeth Pharmaceuticals Inc, Philadelphia, PA], serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F) is effective in preventing vaccine-serotype pneumococcal disease. 13-Valent pneumococcal conjugate vaccine (PCV13) (PCV7 serotypes plus 1, 3, 5, 6A, 7F, and 19A) was designed to provide broader pneumococcal disease coverage. We evaluated the immunogenicity and safety of PCV13 compared with PCV7. METHODS: Infants received PCV13 or PCV7 at ages 2, 4, 6, and 12 to 15 months with routine pediatric vaccinations. Pneumococcal anticapsular polysaccharide-binding immunoglobulin G responses and functional antipneumococcal opsonophagocytic activity were assessed 1 month after dose 3, before the toddler dose, and 1 month after the toddler dose. Safety and tolerability were also assessed. RESULTS: For the 7 common serotypes, PCV13-elicited immunoglobulin G titers were noninferior to those elicited by PCV7, although PCV13 responses were generally somewhat lower. PCV13 also elicited functional opsonophagocytic activity comparable with that elicited by PCV7. For the 6 additional serotypes in PCV13, PCV13 elicited binding and functional antibody levels notably greater than those in PCV7 recipients. After PCV13 immunization, concordance between antipolysaccharide and opsonophagocytic responses was noted for all 13 serotypes. The PCV13 toddler dose resulted in higher immune responses compared with infant-series doses. Safety and tolerability were comparable; reactogenicity was generally mild. CONCLUSIONS: PCV13 will be as effective as PCV7 in the prevention of pneumococcal disease caused by the 7 common serotypes and could provide expanded protection against the 6 additional serotypes. The PCV13 safety profile was comparable to that of PCV7.

Efficacy, Immunogenicity, and Safety of a Pentavalent Human-Bovine (WC3) Reassortant Rotavirus Vaccine at the End of Shelf Life

BACKGROUND. Rotavirus is the leading cause of dehydrating acute gastroenteritis in infants worldwide. Previous studies of a live pentavalent human-bovine reassortant rotavirus vaccine have shown it to be efficacious across a range of potencies. OBJECTIVE. Our goal was to evaluate the efficacy, immunogenicity, and safety of pentavalent rotavirus vaccine at the end of shelf life in healthy infants. PATIENTS AND METHODS. During 2002–2004, 1312 healthy infants ∼6 to 12 weeks old from the United States (47%) and Finland (53%) were randomly assigned to receive 3 oral doses of vaccine (vaccine at ∼1.1 × 107 infectious U per dose) or placebo ∼4 to 10 weeks apart. Infants were to be followed for acute gastroenteritis through 1 rotavirus season after vaccination and for adverse events postvaccination. RESULTS. Three doses of pentavalent rotavirus vaccine at the end of shelf life demonstrated efficacy against rotavirus gastroenteritis caused by human G-serotypes included in the vaccine (G1–G4). Efficacy against severe rotavirus gastroenteritis was 100%, and efficacy against any rotavirus gastroenteritis regardless of severity was 72.5%. A threefold rise in G1 serum neutralizing was observed in 57% and in anti-rotavirus immunoglobulin A in 96% of pentavalent rotavirus vaccine recipients. No statistically significant increase in vomiting, diarrhea, or irritability was observed among pentavalent rotavirus vaccine recipients compared with placebo recipients within the 7-day period from each dose. A statistically significant increase in fevers (≥100.5°F, rectal equivalent) was observed among pentavalent rotavirus vaccine recipients compared with placebo recipients after dose 1. CONCLUSIONS. This pentavalent human-bovine rotavirus vaccine was generally well tolerated, efficacious, and immunogenic at the end of shelf life.

Infant Immunization with Pneumococcal CRM197 Vaccines: Effect of Saccharide Size on Immunogenicity and Interactions with Simultaneously Administered Vaccines

Six pentavalent pneumococcal conjugate vaccines (Pn-CRM197) were evaluated among 400 infants. The vaccines differed in saccharide chain length (oligosaccharide [OS] or polysaccharide [PS]) and saccharide quantity (0.5, 2, or 5 microg). Subjects were randomized into groups 1-6 (Pn-CRM197 recipients) or 7 (controls) for immunization at 2, 4, and 6 months of age. Pn-CRM197 were well tolerated and elicited mean antibody concentrations that exceeded those in controls for all 5 capsular serotypes. PS formulations were generally more immunogenic than their OS counterparts. For PS vaccines, a dose-response was documented (5 microg > 2 microg > 0.5 microg), but the differences between the 5- and 2-microg formulations were insignificant. The mean anti-PRP antibody concentration was significantly higher among Pn-CRM197 recipients. It is concluded that PS vaccines are more immunogenic than OS vaccines. The improved immunogenicity from Haemophilus type b oligosaccharide conjugate (HbOC) vaccine when given with Pn-CRM197 suggests that a decreased dose of HbOC vaccine may be sufficient to elicit protection.

Long-term Study of a Quadrivalent Human Papillomavirus Vaccine

BACKGROUND: We present a long-term safety, immunogenicity, and effectiveness study of a quadrivalent human papillomavirus (HPV4) vaccine. METHODS: Sexually naive boys and girls aged 9 to 15 years (N = 1781) were assigned (2:1) to receive HPV4 vaccine or saline placebo at day 1 and months 2 and 6. At month 30, the placebo group (n = 482) received HPV4 vaccine following the same regimen and both cohorts were followed through month 96. Subjects ≥16 years were eligible for effectiveness evaluations. The primary objective was to evaluate the long-term anti-HPV6/11/16/18 serological levels. The secondary objective was to estimate vaccine effectiveness against HPV6/11/16/18-related persistent infection or disease. RESULTS: For each of the HPV4 vaccine types, vaccination-induced anti-HPV response persisted through month 96. Among 429 subjects who received HPV4 vaccine at a mean age of 12, none developed HPV6/11/16/18-related disease or persistent infection of ≥12 months’ duration. Acquisition of new sexual partners (among those ≥16 years) was ∼1 per year. Subjects receiving HPV4 vaccine at month 30 (mean age 15 years) had a similar baseline rate of seropositivity to ≥1 of the 4 HPV types to those vaccinated at day 1 (mean age 12 years; 1.9% [9 of 474] vs 1.7% [20 of 1157]); however, 4 of the 9 subjects vaccinated at the later age were seropositive to 3 vaccine types, indicating previous HPV exposure. No new significant serious adverse events were observed for 8 years postvaccination in both genders. CONCLUSIONS: When administered to adolescents, the HPV4 vaccine demonstrated durability in clinically effective protection and sustained antibody titers over 8 years.

Safety and Immunogenicity of a Combination: Measles, Mumps, Rubella and Varicella Vaccine (ProQuad®)

Background: A combination measles, mumps, rubella, and varicella vaccine (ProQuad®, Merck & Co., Inc, West Point, PA) was evaluated in 5 clinical trials. Use of ProQuad® would result in fewer injections for children and would facilitate universal immunization against all 4 diseases. Objective: To describe the combined results obtained from the studies conducted during the clinical development program for ProQuad®. Methods: A total of 5833 healthy children, 12-23 months of age, and 399 healthy children, 4-6 years of age, received 1 or 2 doses of ProQuad® in 5 controlled clinical trials. M-M-R®II and VARIVAX® were used as the control for most studies. Safety was evaluated for 6 weeks postvaccination and immunogenicity was assessed 6 weeks after each dose by a sensitive assay (ELISA or gpELISA). Results: A single dose of ProQuad® in 12- to 23-month-old children was shown to be as immunogenic as a single dose of M-M-R®II and VARIVAX® and was generally well tolerated. ProQuad® can be used concomitantly with other vaccines (hepatitis B and Haemophilus influenzae b). A higher rate of fever was reported after 1 dose of ProQuad® compared to M-M-R®II and VARIVAX®, but fever episodes were transient without long-term sequelae. Both a 2-dose regimen of ProQuad® in 12- to 23-month-olds and use of ProQuad® in place of M-M-R®II at 4-6 years were shown to be immunogenic and well tolerated. The incidence of adverse experiences following a second dose of ProQuad® was lower than that following the initial dose. Conclusions: A single dose of ProQuad® is as immunogenic as M-M-R®II and VARIVAX® and is well tolerated in a 1- or 2-dose schedule. ProQuad® should easily fit into the routine immunization schedule.

Live attenuated influenza vaccine induces cross-reactive antibody responses in children against an A/Fujian/411/2002-like H3N2 antigenic variant strain

Serum antibody titers against the A/Panama/2007/99(H3N2) and A/Fujian/411/2002(H3N2)-like viruses were determined in children 6–35 months of age who received either 1 dose of the inactivated influenza vaccine or the live attenuated influenza vaccine containing the A/Panama strain. Results indicated that the live vaccine induced higher antibody responses than the inactivated vaccine against the A/Panama and A/Fujian-like viruses.

Safety and Immunogenicity of Concurrent Administration of Live Attenuated Influenza Vaccine With Measles-Mumps-Rubella and Varicella Vaccines to Infants 12 to 15 Months of Age

OBJECTIVE. This study evaluated the safety, tolerability, and immunogenicity of live attenuated influenza vaccine administered concurrently with measles-mumps-rubella vaccine and varicella vaccine to healthy children 12 to 15 months of age. METHODS. Children were assigned randomly to receive (1) measles-mumps-rubella vaccine, varicella vaccine, and intranasal placebo on day 0, followed by 1 dose of live attenuated influenza vaccine on days 42 and 72; (2) measles-mumps-rubella, varicella, and live attenuated influenza vaccines on day 0, followed by a second dose of live attenuated influenza vaccine on day 42 and intranasally administered placebo on day 72; or (3) 1 dose of live attenuated influenza vaccine on days 0 and 42, followed by measles-mumps-rubella and varicella vaccines on day 72. Serum samples were collected before vaccination on days 0, 42, and 72. Reactogenicity events and adverse events were collected through day 41 after concurrent vaccinations and through day 10 after administration of live attenuated influenza vaccine or placebo alone. RESULTS. Among 1245 (99.5%) evaluable children, seroresponse rates and geometric mean titers for measles-mumps-rubella vaccine and varicella vaccine were similar with concurrent administration of live attenuated influenza vaccine or placebo (seroresponse rates of ≥96% for measles-mumps-rubella vaccine and ≥82% for varicella vaccine in both groups). Hemagglutinin-inhibiting antibody geometric mean titers and seroconversion rates to influenza strains in live attenuated influenza virus vaccine were similar after the vaccine was administered alone (seroconversion rates of 98%, 92%, and 44% for H3, B, and H1 strains, respectively) or with measles-mumps-rubella and varicella vaccines (seroconversion rates of 98%, 96%, and 43%). The incidences of reactogenicity events and adverse events were similar among treatment groups. CONCLUSIONS. Concurrent administration of live attenuated influenza vaccine with measles-mumps-rubella vaccine and varicella vaccine provided equivalent immunogenicity, compared with separate administration, and was well tolerated.