F. Raúl Velázquez

Bio: F. Raúl Velázquez is an academic researcher from Mexican Social Security Institute. The author has contributed to research in topics: Rotavirus & Diarrhea. The author has an hindex of 17, co-authored 21 publications receiving 3155 citations.

Safety and Efficacy of an Attenuated Vaccine against Severe Rotavirus Gastroenteritis

Abstract: Background The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial. Methods We studied 63,225 healthy infants from 11 Latin American countries and Finland who received two oral doses of either the HRV vaccine (31,673 infants) or placebo (31,552 infants) at approximately two months and four months of age. Severe gastroenteritis episodes were identified by active surveillance. The severity of disease was graded with the use of the 20-point Vesikari scale. Vaccine efficacy was evaluated in a subgroup of 20,169 infants (10,159 vaccinees and 10,010 placebo recipients). Results The efficacy of the vaccine against severe rotavirus gastroenteritis and against rotavirus-associated hospitalization was 85 percent (P<0.001 for the comparison with placebo) and reached 100 percent against more severe rotavirus gastroenteritis. Hospitalization for diarrhea of any cause was reduced by 42 percent (95 percent confidence interval, 29 to 53 percen...

Serum antibody as a marker of protection against natural rotavirus infection and disease.

Abstract: To determine whether naturally acquired serum IgA and IgG antibodies were associated with protection against rotavirus infection and illness, a cohort of 200 Mexican infants was monitored weekly for rotavirus excretion and diarrhea from birth to age 2 years. Serum samples collected during the first week after birth and every 4 months were tested for anti-rotavirus IgA and IgG. Children with an IgA titer >1:800 had a lower risk of rotavirus infection (adjusted relative risk [aRR], 0.21; P 1:6400 were protected against rotavirus infection (aRR, 0.51; P<.001) but not against rotavirus diarrhea. Protective antibody titers were achieved after 2 consecutive symptomatic or asymptomatic rotavirus infections. These findings indicate that serum anti-rotavirus antibody, especially IgA, was a marker of protection against rotavirus infection and moderate-to-severe diarrhea.

Single multiplex polymerase chain reaction to detect diverse loci associated with diarrheagenic Escherichia coli.

Abstract: We developed and tested a single multiplex polymerase chain reaction (PCR) that detects enterotoxigenic, enteropathogenic, enteroinvasive, and Shiga toxin–producing Escherichia coli. This PCR is specific, sensitive, and rapid in detecting target isolates in stool and food. Because of its simplicity, economy, and efficiency, this protocol warrants further evaluation in large, prospective studies of polymicrobial substances. scherichia coli causes disease in humans through diverse mechanisms (1). Classified on basis of their virulence traits, the most well-studied members of the diarrheagenic E. coli group include enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAggEC), and Shiga-toxin–producing E. coli (STEC), also called verocytotoxin-producing or enterohemorrhagic E. coli. ETEC produce secretory toxins (enterotoxins); EPEC adhere intimately to epithelial cells and induce host cell transmembrane signaling; EIEC invade eukaryotic cells; and STEC produce Shiga toxins. Identifying diarrheagenic E. coli in the polymicrobial milieus of stool and food poses challenges. Occasionally, economically detectable phenotypes distinguish such organisms when they are abundant in human stools. For example, sorbitol- and lactose-nonfermenting colonies are typical of E. coli O157:H7 and EIEC (2,3), respectively. However, these phenotypes are nonspecific, and subsidiary testing is needed to confirm the isolate identity. In vitro assays that detect toxins, adherence, or invasion phenotypes can also identify candidate diarrheagenic E. coli. These determinations are often expensive, require special expertise, and employ various detection

Postmarketing surveillance of intussusception following mass introduction of the attenuated human rotavirus vaccine in Mexico.

Abstract: Background:Mexico initiated mass vaccination with the attenuated human rotavirus vaccine (Rotarix) in 2006. This postlicensure study aimed to assess any potential temporal association between vaccination and intussusception in Mexican infants.Methods:Prospective, active surveillance for intussuscept

Safety and Efficacy of a Pentavalent Human–Bovine (WC3) Reassortant Rotavirus Vaccine

Abstract: BACKGROUND: Rotavirus is a leading cause of childhood gastroenteritis and death worldwide. METHODS: We studied healthy infants approximately 6 to 12 weeks old who were randomly assigned to receive ...

Safety and Efficacy of an Attenuated Vaccine against Severe Rotavirus Gastroenteritis

Abstract: Background The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial. Methods We studied 63,225 healthy infants from 11 Latin American countries and Finland who received two oral doses of either the HRV vaccine (31,673 infants) or placebo (31,552 infants) at approximately two months and four months of age. Severe gastroenteritis episodes were identified by active surveillance. The severity of disease was graded with the use of the 20-point Vesikari scale. Vaccine efficacy was evaluated in a subgroup of 20,169 infants (10,159 vaccinees and 10,010 placebo recipients). Results The efficacy of the vaccine against severe rotavirus gastroenteritis and against rotavirus-associated hospitalization was 85 percent (P<0.001 for the comparison with placebo) and reached 100 percent against more severe rotavirus gastroenteritis. Hospitalization for diarrhea of any cause was reduced by 42 percent (95 percent confidence interval, 29 to 53 percen...

General recommendations on immunization; recommendations of the Advisory Committee on Immunization Practices (ACIP)

Abstract: This report is a revision of General Recommendations on Immunization and updates the 2002 statement by the Advisory Committee on Immunization Practices (ACIP) (CDC. General recommendations on immunization: recommendations of the Advisory Committee on Immunization Practices and the American Academy of Family Physicians. MMWR 2002;51[No. RR-2]). This report is intended to serve as a general reference on vaccines and immunization. The principal changes include 1) expansion of the discussion of vaccination spacing and timing; 2) an increased emphasis on the importance of injection technique/age/body mass in determining appropriate needle length; 3) expansion of the discussion of storage and handling of vaccines, with a table defining the appropriate storage temperature range for inactivated and live vaccines; 4) expansion of the discussion of altered immunocompetence, including new recommendations about use of live-attenuated vaccines with therapeutic monoclonal antibodies; and 5) minor changes to the recommendations about vaccination during pregnancy and vaccination of internationally adopted children, in accordance with new ACIP vaccine-specific recommendations for use of inactivated influenza vaccine and hepatitis B vaccine. The most recent ACIP recommendations for each specific vaccine should be consulted for comprehensive discussion. This report, ACIP recommendations for each vaccine, and other information about vaccination can be accessed at CDC's National Center for Immunization and Respiratory Diseases (proposed) (formerly known as the National Immunization Program) website at http//:www.cdc.gov/nip.

Prevention of rotavirus gastroenteritis among infants and children. Recommendations of the Advisory Committee on Immunization Practices (ACIP).

Abstract: Rotavirus is the most common cause of severe gastroenteritis in infants and young children worldwide. Before initiation of the rotavirus vaccination program in the United States in 2006, approximately 80% of U.S. children had rotavirus gastroenteritis by age 5 years. Each year during the 1990s and early 2000s, rotavirus resulted in approximately 410,000 physician visits, 205,000272,000 emergency department visits, and 55,00070,000 hospitalizations among U.S. infants and children, with total annual direct and indirect costs of approximately $1 billion. In February 2006, a live, oral, human-bovine reassortant rotavirus vaccine (RotaTeq(R) [RV5]) was licensed as a 3-dose series for use among U.S. infants for the prevention of rotavirus gastroenteritis, and the Advisory Committee on Immunization Practices (ACIP) recommended routine use of RV5 among U.S. infants (CDC. Prevention of rotavirus gastroenteritis among infants and children: recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2006;55[No. RR-12]). In April 2008, a live, oral, human attenuated rotavirus vaccine (Rotarix(R) [RV1]) was licensed as a 2-dose series for use among U.S. infants, and in June 2008, ACIP updated its rotavirus vaccine recommendations to include use of RV1. This report updates and replaces the 2006 ACIP statement for prevention of rotavirus gastroenteritis. ACIP recommends routine vaccination of U.S. infants with rotavirus vaccine. RV5 and RV1 differ in composition and schedule of administration. RV5 is to be administered orally in a 3-dose series, with doses administered at ages 2, 4, and 6 months. RV1 is to be administered orally in a 2-dose series, with doses administered at ages 2 and 4 months. ACIP does not express a preference for either RV5 or RV1. The recommendations in this report also address the maximum ages for doses, contraindications, precautions, and special situations for the administration of rotavirus vaccine.