Resource impact of managing suspected Middle East respiratory syndrome patients in a UK teaching hospital

Clinical challenges exist in the management of hospitalized patients returning to the UK with potential Middle East respiratory syndrome coronavirus (MERS-CoV) infection, particularly with its clinical overlap with influenza, as demonstrated in this case-series and cost-analysis review of returning Hajj pilgrims. These patients were hospitalized with acute febrile respiratory illness, initially managed as potential MERS-CoV infections, but were eventually diagnosed with influenza. Additional costs were small, yet enhanced infection prevention measures created significant burdens on isolation rooms and staff time. Planning for predictable events such as Hajj is important for resource management. Here, in-house MERS-CoV diagnostic testing would have facilitated earlier diagnosis and discharge.

Differences in the compliance with hospital infection control practices during the 2009 influenza H1N1 pandemic in three countries

BACKGROUND

In December 2009, the World Health Organization (WHO) issued updated guidelines on the prevention of H1N1 influenza virus in healthcare settings. In 2010, the WHO pandemic influenza alert level was still at phase 6.

AIM

To study the practice of infection control measures during the 2009 influenza H1N1 pandemic among healthcare workers (HCWs) in three countries.

METHODS

A standardized, self-administered anonymous questionnaire survey was conducted in 2010 among doctors, nurses and allied HCWs in 120 hospital-based clinical departments in Hong Kong, Singapore and the UK. Questions were asked on demographics; previous experience and perceived severity of influenza; infection control practices; uptake of seasonal influenza vaccination and H1N1 vaccination. Multiple logistic regression was used to test the independent association with different factors.

FINDINGS

A total of 2100 HCWs in the three countries participated. They reported high compliance (>80%) with infection control procedures regarded as standard for droplet-transmitted infections including wearing and changing gloves, and washing hands before and after patient contact. However, the reported use of masks with indirect or direct patient contact (surgical or N95 as required by their hospital) varied considerably (96.4% and 70.4% for Hong Kong; 82.3% and 87.7% for Singapore; 25.3% and 62.0% for the UK). Reported compliance was associated with job title, number of patient contacts and perceived severity of pandemics. There was no association between the uptake for seasonal or 2009 H1N1 vaccines and compliance.

CONCLUSIONS

Compliance with infection control measures for pandemic influenza appears to vary widely depending on the setting.

Observational study to investigate vertically acquired passive immunity in babies of mothers vaccinated against H1N1v during pregnancy

OBJECTIVE

The primary objective was to determine the proportion of babies who acquired passive immunity to A/H1N1v, born to mothers who accepted vaccination as part of the national vaccination programme while pregnant (during the second and/or third trimesters) against the novel A/H1N1v influenza virus (exposed group) compared with unvaccinated (unexposed) mothers.

DESIGN

An observational study at three sites in the UK. The purpose was to determine if mothers immunised against A/H1N1v during the pandemic vaccination period transferred that immunity to their child in utero.

SETTING

Three sites in the UK [Queen's Medical Centre, Nottingham; City Hospital, Nottingham (both forming University Hospitals Nottingham), and Leicester Royal Infirmary (part of University Hospitals Leicester)].

PARTICIPANTS

All pregnant women in the second and third trimester presenting at the NHS hospitals above to deliver were eligible to participate in the study. Women were included regardless of age, social class, ethnicity, gravida and parity status, past and current medical history (including current medications), ethnicity, mode of delivery and pregnancy outcome (live/stillbirth).

INTERVENTIONS

At enrolment, participants provided written consent and completed a questionnaire. At parturition, venous cord blood was obtained for serological antibody analysis. Serological analysis was undertaken by the Respiratory Virus Unit (RVU), Health Protection Agency (HPA) Centre for Infections, London.

MAIN OUTCOME MEASURES

The primary end point in the study was the serological results of the cord blood samples for immunity to A/H1N1v. Regarding a suitable threshold for the determination of a serological response consistent with clinical protection, this issue is somewhat complex for pandemic influenza. The European Medicines Agency (EMEA) Committee for Human Medicinal Products (CHMP) judges that a haemagglutination inhibition (HI) titre of 1 : 40 is an acceptable threshold. However, this level was set in the context of licensing plain trivalent seasonal vaccine, where a titre of 1 : 40 is but one of several related immunogenicity criteria, and supported by paired sera capable of demonstrating a fourfold rise in antibody titre in response to vaccination. The current study mainly investigated the effects of an AS03-adjuvanted monovalent vaccine, and it was not possible to obtain paired sera where the initial sample was taken before vaccination (in vaccinated subjects). Of possibly greater relevance is the fact that it has been established from the study of early outbreaks of pandemic influenza in secondary schools in the UK (HPA, unpublished observations) that an HI antibody titre of 1 : 32 seems to be the threshold for a humoral response to 'wild-type' A/H1N1v infection. On that basis, a threshold of 1 : 32 is at least as appropriate as one of 1 : 40, especially in unvaccinated individuals. Given the difficulties that would accrue by applying thresholds of 1 : 32 in unvaccinated patients and 1 : 40 in vaccinated patients, we have therefore applied a threshold of 1 : 32 and 1 : 40, to increase the robustness of our findings. Differences arising are described. A microneutralisation (MN) titre of 1 : 40 may be also used, although it is not part of the CHMP criteria for vaccine licensure. Nonetheless, we utilised this analysis as a secondary end point, based on a conservative threshold of 1 : 60.

RESULTS

Reverse cumulative distribution percentage curves for haemagglutinin dilution and MN titres demonstrate background immunity in babies of unvaccinated mothers of 25%-30%. Humoral immunity in babies of vaccinated mothers was present in 80% of the group. The difference in positive immunity between the babies of unvaccinated and vaccinated mothers was statistically significant (chi-squared test, p < 0.001).

CONCLUSIONS

Our findings reveal a highly significant difference in HI titres between babies born to mothers vaccinated with pandemic-specific vaccine against A/H1N1v during the 2009-10 pandemic period. The subjects recruited were comparable from a baseline perspective and thus do not represent different groups that otherwise could have introduced bias into the study. Continued circulation of 2009 A/H1N1-like viruses is uncertain, but is possible as seasonal influenza in years to come. It is possible that future seasonal waves may display increased virulence. Given the adverse outcomes experienced for a small proportion of pregnant women during the influenza pandemic of 2009-10, this study provides useful evidence to support vaccination in pregnancy to protect both the mother and baby.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Influenza vaccination and asthma: current studies and recommendations

Influenza is an important epidemic and pandemic illness associated with serious morbidity and mortality in unprotected communities. Patients at increased risk of infection are those with pre-existing cardiopulmonary disease including asthma. The influenza virus has the ability to produce antigenic changes posing problems for vaccine development. Influenza vaccines have been available for over 50 years. Despite the continuing global threat posed by infection and recommendations in many countries that immunisation should be widely given, uptake rates are variable and often poor. It has been demonstrated that infection with influenza and other respiratory viral pathogens can produce exacerbations of asthma throughout the age groups. Despite this, vaccine uptake rates in asthmatic populations are quite low. Poor uptake rates are attributed to a number of factors and we review the evidence for the widely held view that influenza vaccination produces exacerbations of chronic airflow obstruction including asthma. Observational studies have found conflicting results: some post immunisation changes in bronchial hyperreactivity and increased requirements of bronchodilator therapy have been in some, but not all, studies. Placebo-controlled trials have not demonstrated any clinical deterioration although one study showed a small reduction in peak expiratory flow rate. Intranasal administration of cold-adapted live vaccines and new nucleic acid vaccines are briefly considered. Live adapted vaccines have been shown to be effective in influenza immunoprophylaxis and limited data on their use in patients with asthma suggest that they can be administered safely. In conclusion, based up on current studies and evidence, it seems likely that influenza infection produces morbidity in patients with asthma but that any potential adverse effects of influenza immunisation are outweighed by the benefits in this population. However, placebo-controlled trials are few and only small numbers of asthmatic patients have been investigated.

Disseminated Sporothix schenckii in a patient with AIDS

Sporothrix schenckii is a widespread dimorphic fungus which can cause cutaneous infection following local implantation. Disseminated sporotrichosis may occur in immunodeficient individuals but meningitis remains a rare complication. Diagnosis is usually difficult, requiring isolation of the organism from the CSF or skin so appropriate treatment can be promptly initiated. We present the first case of S. schenckii meningitis reported in the UK in a patient with AIDS. He presented with insidious features of meningoencephalitis, hydrocephalus and multiple cutaneous lesions and failed to respond to therapy.

Detection of anti-H5 responses in human sera by HI using horse erythrocytes following MF59-adjuvanted influenza A/Duck/Singapore/97 vaccine

Haemagglutination-inhibition (HI) tests are a simple method used to assess immune responses to influenza haemagglutinin. However, HI tests are insensitive at detection of antibody responses to avian haemagglutinin after vaccination or natural infection, even in the presence of high titres of neutralising antibody or virus isolation. Avian influenza viruses preferentially bind to sialic acid receptors that contain N-acetylneuraminic acid alpha2,3-galactose (alpha2,3Gal) linkages while human viruses preferentially bind to those containing N-acetylneuraminic acid alpha2,6-galactose (alpha2,6Gal) linkages. By using horse erythrocytes in the HI test and thereby increasing the proportion of alpha2,3Gal linkages available for binding, we are able to demonstrate improved detection of antibody to avian H5 in human sera following vaccination with MF59-adjuvanted A/Duck/Singapore/97 surface antigen vaccine. This modified HI test was more sensitive in detection of anti-H5 antibody evoked by revaccination of primed subjects and may be useful in assessing potential avian HA vaccine candidates.

Sialic acid receptor specificity on erythrocytes affects detection of antibody to avian influenza haemagglutinin

Haemagglutination-inhibition tests (HI) are used to detect increases in influenza antibody in serum. However, they are relatively insensitive for the detection of human antibody responses to avian haemagglutinin, even in the presence of high titres of neutralising antibody after confirmed infection or vaccination. Human influenza viruses bind preferentially sialic acid containing N-acetylneuraminic acid alpha2,6-galactose (SAalpha2,6Gal) linkages while avian and equine viruses bind preferentially those containing N-acetylneuraminic acid alpha2,3-galactose (SAalpha2,3Gal) linkages. Increasing the proportion of SAalpha2,3Gal linkages on the erythrocytes used, by enzymatic modification or change of species, improves the ability of erythrocytes to bind to avian influenza strains and thereby improves the sensitivity of detection of antibody to avian and equine HA in a range of mammalian and human sera using HI tests.

Experience with the clinical development of influenza vaccines for potential pandemics

During normal interpandemic influenza seasons, immune responses to vaccines are quite predictable and meet the licensing criteria of the European Union (EU) Committee for Proprietary Medicinal Products (CPMP). In a pandemic situation, large sections, if not all of the community will be immunologically naïve and therefore new immunisation strategies will be needed. In 1976 and 1977 H1N1 vaccines were prepared and tested clinically. To stimulate 'protective' antibody responses, two doses of vaccine were needed in people below the age of 24 years (no previous experience of H1N1 virus), whereas one conventional dose was adequate in older people. In 1997, the highly pathogenic avian influenza H5N1 virus caused widespread concern when it infected man, with lethal effects. Due to safety concerns it was necessary to adopt new strategies for vaccine development and one such strategy was to produce vaccine from an avirulent H5N3 virus, A/Duck/Singapore-Q/F119-2/97. Clinical trials of a subunit vaccine prepared from A/Duck/Sing/97 virus revealed that even two doses of twice the normal vaccine concentration (i.e. 30 micro g haemagglutinin) were poorly immunogenic, whereas an H5N3 vaccine adjuvanted with microfluidised emulsion (MF) 59 stimulated antibody levels that complied with CPMP criteria after two half strength doses (i.e. 7.5 micro g haemagglutinin).

Healthcare workers and their attitudes to influenza vaccination

Despite Department of Health recommendations that healthcare workers (HCWs) receive influenza vaccination, uptake is low. Influenza vaccination has been promoted to reduce nosocomial transmission and staff absenteeism during the winter period. Our study aimed to investigate factors associated with uptake, and non-uptake, of influenza vaccination. In March 2001 we undertook a questionnaire-based cross-sectional survey of 604 hospital HCWs in Leicester and 11 occupational health nurses. Following multivariate analysis, uptake was associated with previous influenza vaccination (OR: Odds ratio 1000, 95% CI 20-3,333), age > 45 years (OR 4.45, 95% CI 1.66-11.9), and belief that influenza is a serious illness (OR 3.8, 95% CI 1.3-10.6). HCWs receive vaccination predominantly as a benefit for themselves. Campaigns should improve accessibility, target younger staff and stress the consequences of influenza infection. Simply raising awareness may not translate into increased uptake. Absenteeism was attributed to vaccine-related adverse effects by 11/83 (13%) vaccinees, resulting in 0.46 workdays lost per dose administered.

The epidemiology of influenza

Influenza remains a globally important cause of febrile respiratory illness. Influenza virus activity in the community results in significant mortality, morbidity and economic disruption, particularly in those at high risk of developing complications, such as the elderly and those with underlying chronic medical conditions, including pulmonary disease and diabetes mellitus. The occurrence in Hong Kong in 1997 of avian influenza H5N1 in man, which resulted in six deaths, served to remind us of the importance of continuing surveillance and preparation for the next pandemic.

Safety and antigenicity of non-adjuvanted and MF59-adjuvanted influenza A/Duck/Singapore/97 (H5N3) vaccine: a randomised trial of two potential vaccines against H5N1 influenza

BACKGROUND

In 1997, pathogenic avian influenza A/Hong Kong/97 (H5N1) viruses emerged as a pandemic threat to human beings. A non-pathogenic variant, influenza A/Duck/Singapore/97 (H5N3), was identified as a leading vaccine candidate. We did an observer-blind, phase I, randomised trial in healthy volunteers to assess safety, tolerability, and antigenicity of MF59-adjuvanted and non-adjuvanted vaccines.

METHODS

32 participants were randomly assigned MF59, and 33 non-adjuvanted vaccine. Two doses were given 3 weeks apart, of 7.5, 15, or 30 microg haemagglutinin surface-antigen influenza A H5N3 vaccine. Antibody responses were measured by haemagglutination inhibition, microneutralisation, and single radial haemolysis (SRH). The primary outcome was geometric mean antibody titre 21 days after vaccination.

FINDINGS

The A/Duck/SIngapore vaccines were safe and well tolerated. Antibody response to non-adjuvanted vaccine was poor, the best response occurring after two 30 microgram doses: one, four, four, and one person of eleven seroconverted by haemagglutination inhibition, microneutralisation, H5N3 SRH, and H5N1 SRH, respectively. The geometric mean titres of antibody, and seroconversion rates, were significantly higher after MF59 adjuvanted vaccine. Two 7.5 microg doses of MF59 adjuvanted vaccine gave the highest seroconversion rates: haemagglutination inhibition, six of ten; microneutralisation, eight of ten; H5N3 SRH, ten of ten; H5N1 SRH, nine of ten. Geometric mean titre of antibody to the pathogenic virus, A/Hong Kong/489/97 (H5N1), was about half that to A/Duck/Singapore virus.

INTERPRETATION

Non-adjuvanted A/Duck/Singapore/97 (H5N3) vaccines are poorly immunogenic and doses of 7.5-30 microg haemagglutinin alone are unlikely to give protection from A/Hong Kong/97 (H5N1) virus. Addition of MF59 to A/Duck/Singapore/97 vaccines boost the antibody response to protection levels. Our findings have implications for development and assessment of vaccines for future pandemics.

Influenza: vaccination and treatment

Few conditions exert such an enormous toll of absenteeism, suffering, medical consultations, hospitalization, death and economic loss as influenza. Patients at high risk of complications and mortality include the elderly and those with pre-existing cardiopulmonary disease. The outbreak in 1997 in Hong Kong, of avian H5N1 influenza in man, which resulted in six deaths among 18 hospitalized cases, and the recent isolation of H9N2 viruses from two children in Hong Kong, are reminders that preparation must be made for the next pandemic. Since the 1970s, efforts to control influenza have mostly focussed on the split product and surface antigen vaccines. These vaccines are of proven efficacy in healthy adults and are effective in elderly people with and without medical conditions putting them at high risk of complications and death following influenza infection. However, vaccine coverage is patchy and often low, and outbreaks of influenza are not uncommon in well-immunized residents of nursing homes. New vaccines and methods of vaccine delivery are being developed in attempts to overcome the limitations of existing vaccines. The antiviral drugs amantadine and rimantadine were developed in the 1960s, but have not been used widely due to their spectrum of activity, rapid emergence of resistance, and adverse effects associated with amantadine. The site of enzyme activity of the influenza neuraminidase is highly conserved between types, subtypes and strains of influenza and has emerged as the target of an exciting new class of antiviral agents that are effective both prophylactically and as therapy.

Drug treatment of tropical parasitic infections: recent achievements and developments

Drug development offers potential solutions to a number of tropical health diseases, although the expense of pharmaceutical research and lack of return on investment has limited the production of new agents. The greatest successes have been through the development of single dose therapy and mass treatment control programmes for a number of diseases. We review some of the current treatment regimens for malaria, intestinal helminth infection, onchocerciasis, filariasis and schistosomiasis, and their use in clinical practice. Geographical spread and emergence of drug resistant parasites have hindered the control of malaria, the most important global parasitic infection. Artemisinin compounds have proved effective antimalarial agents producing rapid reduction of parasite load and can be used in combination treatment regimens to combat multidrug resistance. Intestinal helminth infections are widespread, giving rise to nutritional deficiencies and impaired childhood cognitive development. Pregnant women in developing countries are at increased risk of morbidity. Treatment with a single dose benzimidazole such as albendazole or mebendazole has beneficial effects on morbidity and rates of transmission. Diethylcarbamazine has been used in the treatment of onchocerciasis and human filariasis. A complicated escalating dose regimen over several weeks is associated with systemic and allergic reactions and may require corticosteroid cover. Simplified regimens for mass population treatment with ivermectin have proved useful and been used in combination with single dose albendazole and diethylcarbamazine. The African Programme for Onchocerciasis Control in West and Central Africa has been one of the most successful mass control programmes virtually eliminating new infections by a combination of chemotherapy, education and vector control. Schistosomiasis is of increasing importance as a result of the creation of new snail habitats by agricultural and economic development. Praziquantel has become the most widely available and effective chemotherapy for schistosomiasis. There have been a number of reports of persistent schistosome egg shedding after treatment posing concerns about the emergence of drug resistance. Eflornithine has been successfully used in patients with human trypanosomiasis failing melarsoprol therapy however expense and availability have limited its potential. Mass control treatment programmes have targeted schoolchildren, adolescents and pregnant women. The integration of schistosomiasis, onchocerciasis, filariasis and helminth control programmes has been considered as a cost-effective method of delivering treatment. It is likely that future control will be based on this optimisation and integration of existing regimens, rather than the development of new agents.