Search

Sera from 147 volunteers were examined for vibriocidal antibody by the tube-dilution method before and after they ingested 10(3)-10(6) Vibrio cholerae organisms. Titers increased significantly after challenge in 97% of 110 persons who excreted V. cholerae. In 12% of the bacteriologically confirmed infections, the titer increased significantly only to the homologous (Inaba or Ogawa) serotype. Levels of vibriocidal antibody decreased substantially between one and six months after challenge, but they usually remained elevated over base-line values. Levels of antitoxin to V. cholerae were measured by IgG enzyme-linked immunosorbent assay (ELISA), rabbit skin permeability tests, and adrenal cell techniques in 73 pairs of prechallenge and postchallenge sera. Results of the vibriocidal assay agreed most closely with those of the ELISA, the most sensitive antitoxin assay, in serologically detecting clinical and subclinical infections. Recent infection could be accurately serodiagnosed by levels of vibriocidal antibody and antitoxin (by IgG ELISA) in a convalescent-phase serum. more...

To ascertain whether subjects infected with human immunodeficiency virus (HIV) generally develop protective hemagglutination inhibition antibody responses to inactivated influenza vaccines.Prospective study of 104 persons before and after immunization.Outpatient clinic and hospital ward.Persons with the acquired immunodeficiency syndrome (AIDS) (n = 25), AIDS-related complex (n = 14), and HIV-seropositive men with only lymphadenopathy or no symptoms (n = 27). Controls were HIV-seronegative homosexual men (n = 22) and HIV-seronegative heterosexuals (n = 16).Subjects were immunized with inactivated vaccines containing 15 micrograms of each of the following influenza virus hemagglutinins: A/Taiwan/1/86 (HINI), A/Mississippi/1/85 (H3N2), A/Chile/1/83 (HINI), and B/Ann Arbor/1/86.Fourfold or greater antibody responses occurred less frequently in subjects with HIV infections than in HIV-seronegative controls. Protective levels (1:64 or greater) of hemagglutination inhibition antibodies were attained by 94% to 100% of HIV-seronegative controls, 52% to 89% of HIV-seropositive asymptomatic subjects, and 13% to 50% of subjects with AIDS or AIDS-related complex. No increase in the prevalence or level of serum HIV p24 antigen or clinical deterioration was detected among HIV-infected persons after influenza immunization.Because of the poor antibody responses to influenza vaccines among HIV-infected subjects, even in many with no or minimal symptoms, alternative strategies for preventing influenza, such as booster doses of influenza vaccine, prophylaxis with amantidine, or both should be considered. more...

An attenuated influenza A candidate vaccine virus, derived from the A/Ann Arbor/6/60 (H2N2) cold-adapted (ca) donor virus and the A/Alaska/6/77 (H3N2) wild-type virus, was evaluated in adult seronegative volunteers (serum hemagglutination-inhibiting antibody titer, less than or equal to 1:8) for level of attenuation, infectivity, antigenicity, and genetic stability. Four groups with similar preinoculation mean titers of serum and nasal wash antibodies were inoculated intranasally with 10(4.5), 10(5.5), 10(6.5), or 10(7.5) 50% tissue culture infectious doses (TCID50) of the ca reassortant virus, and eight other seronegative adult volunteers received the wild-type virus. Only 2 of 66 vaccinees developed fever or mild and brief systemic or upper respiratory tract illness or both. Both volunteers with vaccine-related reactions received the highest dose (10(7.5) TCID50) of ca virus, which indicates that the vaccine retains some mild reactogenicity at a high dosage. In contrast, four of eight volunteers infected with the wild-type virus became ill. Each of the 54 isolates tested retained the temperature-sensitive phenotype of the vaccine virus. Thus, the ca reassortant was genetically stable and attenuated at 10(4.5) to 10(7.5) TCID50 for seronegative adults. The 50% human infective dose of ca virus was approximately 10(5.3) TCID50. Ten and one hundred 50% human infectious doses infected 73 and 83% of vaccinees, respectively, and approximately 75% developed an immunological response at these doses. The failure of the vaccine virus to infect some volunteers was correlated with the presence of pre-inoculation nasal wash immunoglobulin A hemagglutinin antibody. more...

Vibrio cholerae O1 A-B- vaccine strain JBK 70 and A-B+ CVD 101 prepared by recombinant DNA techniques from pathogenic EI Tor Inaba N16961 and classical Ogawa 395, respectively, were fed to 38 volunteers in single doses of 10(4) to 10(10). Although severe diarrhea did not occur in any vaccine, more than one-half developed mild diarrhea. These attenuated strains colonized well and elicited prominent vibriocidal and antitoxic (CVD 101) antibody responses. Recipients of a single dose of JBK 70 were significantly protected when challenged with 10(6) wild-type N16961. Diarrhea occurred in 7 of 8 controls but in only 1 of 10 vaccines (P less than 0.003, 89% vaccine efficacy), demonstrating the potency of immune mechanisms that do not involve cholera antitoxin. Further derivatives were prepared to explore the pathogenesis of the residual diarrhea, considering that either intestinal colonization by the vaccine itself or accessory toxins might be responsible. CVD 102, an auxotrophic mutant of CVD 101, did not cause diarrhea but colonized poorly and elicited feeble immune responses. Derivatives of JBK 70 and CVD 101 (CVD 104 and 105) deleted of genes encoding the EI Tor hemolysin still caused mild diarrhea. Genetically engineered strains can be colonizing, highly immunogenic, and protective single-dose oral vaccines, but they must be further attenuated before they can be considered for use as public health tools. more...

The transfer of six internal RNA segments from the avian influenza A/Mallard/New York/6750/78 (H2N2) virus reproducibly attenuates human influenza A viruses for squirrel monkeys and adult humans. To identify the avian influenza A virus genes that specify the attenuation and host range restriction of avian-human (ah) influenza A reassortant viruses (referred to as ah reassortants), we isolated six single-gene reassortant viruses (SGRs), each having a single internal RNA segment of the influenza A/Mallard/New York/6750/78 virus and seven RNA segments from the human influenza A/Los Angeles/2/87 (H3N2) wild-type virus. To assess the level of attenuation, we compared each SGR with the A/Los Angeles/2/87 wild-type virus and a 6-2 gene ah reassortant (having six internal RNA segments from the avian influenza A virus parent and two genes encoding the hemagglutinin and neuraminidase glycoproteins from the wild-type human influenza A virus) for the ability to replicate in seronegative squirrel monkeys and adult human volunteers. In monkeys and humans, replication of the 6-2 gene ah reassortant was highly restricted. In humans, the NS, M, PB2, and PB1 SGRs each replicated significantly less efficiently (P less than 0.05) than the wild-type human influenza A virus parent, suggesting that each of these genes contributes to the attenuation phenotype. In monkeys, only the NP, PB2, and possibly the M genes contributed to the attenuation phenotype. These discordant observations, particularly with regard to the NP SGR, indicate that not all genetic determinants of attenuation of influenza A viruses for humans can be identified during studies of SGRs conducted with monkeys. The PB2 and M SGRs that were attenuated in humans each exhibited a new phenotype that was not observed for either parental virus. Thus, it was not possible to determine whether avian influenza virus PB2 or M gene itself or a specific constellation of avian and human influenza A virus specified restriction of virus replication in humans. more...

An enzyme immunoassay (EIA) was developed to measure serum antibody responses of healthy adult volunteers vaccinated with 40 or 80 μg of human immunodeficiency virus type 1 (HIV-1) recombinant gp16... more...

PIP: Doctors Kahn and Blum based their views on oral rehydration on only 7 cases, and they fail to provide their methodological details. In their letter on oral rehydration with UNICEF/WHO (United Nations International Children's Emergency Fund/World Health Organization) glucose electrolyte solution (GES), they maintain that hyperkalemia is a danger of GES therapy, that hypernatremia will be aggravated, that therapy should not last for longer than 24 hours, that after 24 hours monitoring of plasma potassium will be needed, and that except for developing countries where material milk is used, no plan of treatment has been proposed after the first 24 hours of rehydration. The experience of Kahn and Blum is at variance with extensive data from many carefully monitored balanced studies in infants treated with GES. GES is a potent medication and needs to be used properly. Guidelines for use are listed. Kahn and Blum fail to indicate whether their 7 patients comprised their entire treatment group or only those with biochemical or clinical problems. They also fail to indicate the degree of dehydration of the infants at onset of therapy or the extent of ongoing diarrheal losses, and they do not describe the precise treatment regimen. Their mean time of treatment -- 41 hours -- was particularly long. The hyperkalemia reported by Kahn and Blum may have resulted from excessive GES administration, without a source of free water, to infants having few diarrheal stools. Proper use of GES formula rapidly rehydrates 95-98% of mildly to severely dehydrated infants, irrespective of etiology. more...

Inactivated influenza vaccines confer incomplete and transient protection from disease, and the whole-virus inactivated vaccines cause high rates of reactions in children. Live, attenuated vaccines have been developed from cold-adapted (CA) and avian-human (AH) influenza virus reassortants, and are safe and effective in adults. We compared the infectious dose50, immunogenicity, reactogenicity and transmissability of CA and AH influenza A/Bethesda/85 (H3N2) reassortant vaccines in young children. Fifty-eight seronegative 6 to 36 months old children were studied in groups of 6 to 10 in close contact in a day-care-like setting for 2 days before and 9 days after receiving a placebo or 103 to 106 TCID50 of either vaccine. Seroconversion occurred in >50% of children who received a dose of 106 TCID50 of either vaccine. There were no differences in rates of febrile or respiratory illness between vaccinees and placebo recipients. Vaccine virus was shed in low titers (5.6 to 27.5 TCID50/ml) for 1 to 5 days by vaccinees, and no transmission to placebo contacts occurred. Both vaccines appear to be safe and immunogenic in young children and infants. more...

International Perspectives on Neglected Sexually Transmitted Diseases: Impact on Venereology, Infertility, and Maternal and Infant Health, edited by King K. Holmes and Per-Anders Mardh (WHO Scientific Group meeting), 336 pp, with illus, $44.50, Washington, DC, Hemisphere Publishing Corp; New York, McGraw-Hill Book Co, 1983. At a time when sexually transmitted diseases (STDs) have captured the interest of the medical community and the public, two new books dealing with the topic are available. Both are multiauthored by recognized experts. The field of STDs is changing so rapidly that both books (whose references to original research are not more recent than 1981) are unavoidably out of date. Therefore, to learn about current topics of interest, such as the acquired immune deficiency syndrome (AIDS) and chemotherapy for genital herpes, the reader of these books must turn to recent journal articles.The more general of the two books, Diagnosis and Treatment of Sexually Transmitted more...

The Restless Tide , a collection of delightful essays, provides an absorbing overview of the historical origins of and recent advances in microbiology and immunology. The book also addresses issues concerning the usefulness of biomedical research and the quality of medical education and medical care. These essays were adapted from public lectures that the author delivered during his first five years as director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health. Written in an entertaining, narrative style, these 11 essays present a current and broad perspective on different aspects of medicine. Each recalls the origins of current achievements, traces their evolution, gives an up-to-date account of each field discussed, and comments on the future research strategies required for over-coming present obstacles. Topics covered include recent advances in the control of infectious diseases by treatment or immunizations; the chameleon nature of microbes—shifts in antigenic constitution more...

We studied whether a two-dose regimen of inactivated influenza virus vaccine was more effective than a single dose in inducing protective hemagglutinationinhibition antibody responses in patients infected with human immunodeficiency virus (HIV). Participants included subjects with acquired immunodeficiency syndrome, subjects with acquired immunodeficiency syndrome—related complex, and HIV-seropositive individuals with either lymphadenopathy only or no symptoms. Control subjects were HIV-seronegative heterosexuals and HIV-seronegative homosexuals. Two doses of inactivated influenza vaccine containing 15 μg of the hemagglutinin of influenza A/Taiwan/1/86(H1N1), A/Leningrad/360/86(H3N2), and B/Ann Arbor/1/86 were administered intramuscularly in the deltoid region 1 month apart. The second dose of vaccine did not significantly increase the frequency or magnitude of antibody responses of either HIV-seropositive or HIV-seronegative subjects over that achieved by a single dose. The two-dose regimen induced a protective level (≥1:64) of hemagglutination-inhibition antibody to influenza A(H1N1) or (H3N2) virus less often in subjects with symptomatic HIV infection than in uninfected control subjects (39% vs 87% or 46% vs 97%, respectively). Our results suggest that a substantial proportion of individuals with symptomatic HIV infection might remain unprotected from influenza, even after immunization with a two-dose regimen. ( JAMA . 1989;262:779-783) more...