Displaying publications 21 - 40 of 89 in total

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  1. Hussain AI, Cordeiro M, Sevilla E, Liu J
    Vaccine, 2010 May 14;28(22):3848-55.
    PMID: 20307595 DOI: 10.1016/j.vaccine.2010.03.005
    Currently MedImmune manufactures cold-adapted (ca) live, attenuated influenza vaccine (LAIV) from specific-pathogen free (SPF) chicken eggs. Difficulties in production scale-up and potential exposure of chicken flocks to avian influenza viruses especially in the event of a pandemic influenza outbreak have prompted evaluation and development of alternative non-egg based influenza vaccine manufacturing technologies. As part of MedImmune's effort to develop the live attenuated influenza vaccine (LAIV) using cell culture production technologies we have investigated the use of high yielding, cloned MDCK cells as a substrate for vaccine production by assessing host range and virus replication of influenza virus produced from both SPF egg and MDCK cell production technologies. In addition to cloned MDCK cells the indicator cell lines used to evaluate the impact of producing LAIV in cells on host range and replication included two human cell lines: human lung carcinoma (A549) cells and human muco-epidermoid bronchiolar carcinoma (NCI H292) cells. The influenza viruses used to infect the indicators cell lines represented both the egg and cell culture manufacturing processes and included virus strains that composed the 2006-2007 influenza seasonal trivalent vaccine (A/New Caledonia/20/99 (H1N1), A/Wisconsin/67/05 (H3N2) and B/Malaysia/2506/04). Results from this study demonstrate remarkable similarity between influenza viruses representing the current commercial egg produced and developmental MDCK cell produced vaccine production platforms. MedImmune's high yielding cloned MDCK cells used for the cell culture based vaccine production were highly permissive to both egg and cell produced ca attenuated influenza viruses. Both the A549 and NCI H292 cells regardless of production system were less permissive to influenza A and B viruses than the MDCK cells. Irrespective of the indicator cell line used the replication properties were similar between egg and the cell produced influenza viruses. Based on these study results we conclude that the MDCK cell produced and egg produced vaccine strains are highly comparable.
  2. Souza AR, Braga JA, de Paiva TM, Loggetto SR, Azevedo RS, Weckx LY
    Vaccine, 2010 Jan 22;28(4):1117-20.
    PMID: 20116631 DOI: 10.1016/j.vaccine.2009.05.046
    The immunogenicity and tolerability of virosome and of split influenza vaccines in patients with sickle cell anemia (SS) were evaluated. Ninety SS patients from 8 to 34 years old were randomly assigned to receive either virosome (n=43) or split vaccine (n=47). Two blood samples were collected, one before and one 4-6 weeks after vaccination. Antibodies against viral strains (2006) A/New Caledonia (H1N1), A/California (H3N2), B/Malaysia were determined using the hemagglutinin inhibition test. Post-vaccine reactions were recorded over 7 days. Seroconversion rates for H1N1, H3N2 and B were 65.1%, 60.4% and 83.7% for virosome vaccine, and 68.0%, 61.7% and 68.0% for split vaccine. Seroprotection rates for H1N1, H3N2 e B were 100%, 97.6% and 69.7% for virosome, and 97.8%, 97.8% and 76.6% for split vaccine. No severe adverse reactions were recorded. Virosome and split vaccines in patients with sickle cell anemia were equally immunogenic, with high seroconversion and seroprotection rates. Both vaccines were well tolerated.
  3. Mariappan V, Vellasamy KM, Thimma JS, Hashim OH, Vadivelu J
    Vaccine, 2010 Feb 3;28(5):1318-24.
    PMID: 19944788 DOI: 10.1016/j.vaccine.2009.11.027
    Burkholderia cepacia is an opportunistic human pathogen associated with lung infections. Secretory proteins of B. cepacia are known to be involved in virulence and may mediate important host-pathogen interactions. In the present study, secretory proteins isolated from B. cepacia culture supernatant were separated using two-dimensional gel electrophoresis, followed by Western blot analysis to identify the immunogenic proteins. Mice antibodies raised to B. cepacia inactivated whole bacteria, outer membrane protein and culture filtrate antigen detected 74, 104 and 32 immunogenic proteins, respectively. Eighteen of these immunogenic proteins which reacted with all three antibodies were identified and might be potential molecules as a diagnostic marker or a putative candidate vaccine against B. cepacia infections.
  4. Camilloni B, Neri M, Lepri E, Iorio AM
    Vaccine, 2009 Jun 24;27(31):4099-103.
    PMID: 19410623 DOI: 10.1016/j.vaccine.2009.04.078
    This study evaluated whether MF59-adjuvanted subunit trivalent influenza vaccine for the 2003/04 winter season (A/Moscow/10/99, H3N2; A/New Caledonia/20/99, H1N1; B/Hong Kong/330/01) would confer protection against mismatched and frequently co-circulating variants of influenza B/Victoria- and B/Yamagata-like virus strains. Haemagglutination inhibiting (HI) antibodies were measured in middle-aged and elderly volunteers against the homologous B/Victoria-like vaccine strain (B/Hong Kong/330/01) and against mismatched B/Victoria-like (B/Malaysia/2506/04) and B/Yamagata-like (B/Singapore/379/99 and B/Shanghai/361/02) strains. Immunization induced significant increases in the amounts of HI antibodies against all influenza B strains under investigation. However, the responses against the heterologous B/Shanghai/361/02 virus did not reach the desirable values of seroprotection. An age-dependent decline of the responses was found for B/Victoria-like antigens, but not for B/Yamagata-like strains. Although further studies are needed, our data support the recommendation of including influenza B viruses of the B/Victoria and B/Yamagata lineages in the future influenza vaccine preparations.
  5. Lum LC, Borja-Tabora CF, Breiman RF, Vesikari T, Sablan BP, Chay OM, et al.
    Vaccine, 2010 Feb 10;28(6):1566-74.
    PMID: 20003918 DOI: 10.1016/j.vaccine.2009.11.054
    Children aged 11 to <24 months received 2 intranasal doses of live attenuated influenza vaccine (LAIV) or placebo, 35+/-7 days apart. Dose 1 was administered concomitantly with a combined measles, mumps, and rubella vaccine (Priorix). Seroresponses to measles and mumps were similar between groups. Compared with placebo, response rates to rubella in LAIV+Priorix recipients were statistically lower at a 15 IU/mL threshold (83.9% vs 78.0%) and the prespecified noninferiority criteria were not met. In a post hoc analysis using an alternate widely accepted threshold of 10 IU/mL, the noninferiority criteria were met (93.4% vs 89.8%). Concomitant administration with Priorix did not affect the overall influenza protection rate of LAIV (78.4% and 63.8% against antigenically similar influenza strains and any strain, respectively).
    Matched MeSH terms: Measles-Mumps-Rubella Vaccine/administration & dosage; Measles-Mumps-Rubella Vaccine/immunology*
  6. Chai PF, Lee WS
    Vaccine, 2009 Nov 20;27 Suppl 5:F112-5.
    PMID: 19931708 DOI: 10.1016/j.vaccine.2009.08.069
    From August 2006 to July 2007 a prospective study of out-of-pocket costs incurred by care-givers of children hospitalized for rotavirus gastroenteritis was conducted in a hospital in Malaysia. Data on caretaker out-of-pocket costs were collected from 260 children hospitalized with diarrhoea. A stool sample was collected from 198 of these children of which 46 (23%) were positive for rotavirus by latex agglutination assay. The mean (median; interquartile range) out-of-pocket cost incurred by the care-givers was US$194 (US$169; US$47-738), constituting 26% of average monthly income of the households surveyed. Major components of the cost were hospital expenses (45%) and productivity loss (37%). These findings will allow further assessment of the cost-effectiveness of any future rotavirus immunization program in Malaysia.
  7. Sagara I, Dicko A, Ellis RD, Fay MP, Diawara SI, Assadou MH, et al.
    Vaccine, 2009 May 18;27(23):3090-8.
    PMID: 19428923 DOI: 10.1016/j.vaccine.2009.03.014
    A double blind, randomized, controlled Phase 2 clinical trial was conducted to assess the safety, immunogenicity, and biologic impact of the vaccine candidate Apical Membrane Antigen 1-Combination 1 (AMA1-C1), adjuvanted with Alhydrogel. Participants were healthy children 2-3 years old living in or near the village of Bancoumana, Mali. A total of 300 children received either the study vaccine or the comparator. No impact of vaccination was seen on the primary endpoint, the frequency of parasitemia measured as episodes >3000/microL/day at risk. There was a negative impact of vaccination on the hemoglobin level during clinical malaria, and mean incidence of hemoglobin <8.5 g/dL, in the direction of lower hemoglobin in the children who received AMA1-C1, although these differences were not significant after correction for multiple tests. These differences were not seen in the second year of transmission.
  8. Bravo LC, Asian Strategic Alliance for Pneumococcal Disease Prevention (ASAP) Working Group
    Vaccine, 2009 Dec 9;27(52):7282-91.
    PMID: 19393708 DOI: 10.1016/j.vaccine.2009.04.046
    This paper represents a collaborative effort by the Asian Strategic Alliance for Pneumococcal Disease Prevention (ASAP) Working Group to collate data on the disease burden due to invasive pneumococcal disease (IPD) in participating Asian countries and territories; namely, Hong Kong, India, Indonesia, Korea, Macau, Malaysia, Pakistan, the Philippines, Singapore, Sri Lanka, Taiwan and Thailand. A review of both published and unpublished data revealed that the incidence of IPD in some countries is well documented by way of large, long-duration studies, while in other countries, much of the available data have been extrapolated from international studies or have come from small population studies of limited geographical coverage. This paper confirms that data regarding the incidence of IPD in Asia are grossly lacking and reinforces the need for urgent and more substantial studies.
  9. Domingo EJ, Noviani R, Noor MR, Ngelangel CA, Limpaphayom KK, Thuan TV, et al.
    Vaccine, 2008 Aug 19;26 Suppl 12:M71-9.
    PMID: 18945416 DOI: 10.1016/j.vaccine.2008.05.039
    Cervical cancer remains one of the leading causes of cancers in women from Indonesia, Malaysia, the Philippines, Thailand and Vietnam. High-risk human papillomavirus (HPV) types, particularly HPV-16 and 18, are consistently identified in cervical cancer cases regardless of geographical region. Factors that have been identified to increase the likelihood of HPV exposure or subsequent development of cervical cancer include young age at first intercourse, high parity and multiple sexual partners. Cervical cancer screening programs in these countries include Pap smears, single visit approach utilizing visual inspection with acetic acid followed by cryotherapy, as well as screening with colposcopy. Uptake of screening remains low in all regions and is further compounded by the lack of basic knowledge women have regarding screening as an opportunity for the prevention of cervical cancer. Prophylactic HPV vaccination with the quadrivalent vaccine has already been approved for use in Malaysia, the Philippines and Thailand, while the bivalent vaccine has also been approved in the Philippines. However, there has been no national or government vaccination policy implemented in any of these countries.
  10. Wong LP
    Vaccine, 2009 Feb 25;27(9):1410-5.
    PMID: 19150379 DOI: 10.1016/j.vaccine.2008.12.045
    This qualitative study used focus group discussions (FGDs) to evaluate information needed in order to make informed human papillomavirus (HPV) vaccination decision, opinion on the most acceptable public education messages, and channel of delivery in a multiethnic, multicultural and multireligion country. A total of 19 FGDs were conducted among mothers of eligible vaccinees, young women eligible for the vaccine, and men. Messages that carry accurate information about HPV-cervical cancer link, the HPV preventive vaccines and at the same time minimize the stigma of a sexually transmitted infection (STI) vaccine were preferred. Educational messages for future HPV educational intervention were developed and methods to effectively convey to the public the need for HPV vaccination were identified. The findings serve as a basis for future intervention to develop research-based communication materials and strategies.
  11. Wong LP
    Vaccine, 2009 Mar 4;27(10):1622-7.
    PMID: 19100803 DOI: 10.1016/j.vaccine.2008.11.107
    Physicians' experiences in providing human papillomavirus (HPV) immunization were assessed by mailed questionnaire. Response rate of 41.4% was achieved. Malay Muslim physicians were more likely to agree that cultural sensitivity is an issue when recommending HPV vaccines. Pediatricians and family physicians were more likely to agree that acceptance is better if vaccines were recommended to prevent cervical cancer than to prevent a sexually transmitted disease. Near 70% rated success of HPV vaccines recommendation in their practice as very poor with the majority patients preferred to postpone immunization. Physicians reported cultural disparities in vaccine uptake and perceived high vaccination cost limits its use.
  12. Vaccine, 2006 Nov 10;24(44-46):6791-2.
    PMID: 17167887
    ESWI recommends that the 25 European Union nations strive to vaccinate one-third of their collective population every year by 2010. This translates into an annual vaccine usage of 150 million doses for a population of 455 million. However, the current vaccine usage in Europe is 79 million doses, meaning that only 40% of ESWI's recommended target population is being vaccinated in the EU-25. Indeed, the EU's current risk groups equal about 28% of its population, but it is estimated that less than 62% are being vaccinated with the current vaccine supply--the equivalent of 17% of the total population. Clearly, as ESWI noted in its concluding position paper at the Malta conference, "a large proportion of those traditionally assumed to be at most risk from influenza are not being vaccinated." How to change this and minimize the consequences of a pandemic? "It's very interesting how the arithmetic works, given the goal of immunizing 75 percent of Europe's high-risk group, " said Dr K.Nichol of the University of Minnesota Medical Center who chaired the session. "If you go from a trivalent vaccine to a monovalent one, then you triple the number of doses you can manufacture. Thus, you could produce enough doses for the entire population of the EU." However, there is no coordinated approach in Europe, meaning such an optimistic scenario is unlikely in the medium-term. For the time being, emphasis must be on raising public awareness and raising vaccination rates at the local level, starting with health care workers themselves. Here the role and attitude of health policy officials and--critically--health care workers are crucial. These front-line policy and healthcare professionals constitute both the problem and the solution to a more effective influenza vaccine effort in Europe: they know first-hand the institutional obstacles blocking progress--i.e., lack of resources, poorly focused public information campaigns, etc.--but their own work practices and attitudes can be misdirected, too. To identify the issues and help the participants produce a set of recommendations, ESWI brought in Penny Lawson from to facilitate Dr.K. Nichol to steer this session's workshop debate. The participants were a diverse group of 35 health care workers from Australia, Finland, France, Germany, Malaysia, Malta, Netherlands, Norway, Poland, Portugal, Spain, Sweden and the UK.
  13. Rapeah S, Norazmi MN
    Vaccine, 2006 Apr 24;24(17):3646-53.
    PMID: 16494975 DOI: 10.1016/j.vaccine.2006.01.053
    Recombinant Mycobacterium bovis bacille Calmette-Guèrin (rBCG) expressing the malarial epitopes F2R(II)EBA and (NANP)3 as well as two T cell epitopes of the M. tuberculosis ESAT-6 antigen, generated in favour of mycobacterium codon usage elicited specific immune response against these epitopes. Immunised Balb/c mice demonstrated an increase in almost all of the IgG subclasses against both malarial epitopes and enhanced splenocyte proliferative response against the malarial epitopes as well as selected peptides of ESAT-6. Furthermore, flow cytometric analyses showed elevated numbers of CD4+ lymphocytes expressing IFN-gamma and IL-2 against the ESAT-6 peptides, suggesting a specific Th1-mediated response. This study demonstrated that expressing malarial and TB epitopes in a single rBCG construct induced appropriate humoral and cellular immune response against immunogenic epitopes from both organisms.
    Matched MeSH terms: BCG Vaccine/immunology*
  14. Ravichandran M, Ali SA, Rashid NH, Kurunathan S, Yean CY, Ting LC, et al.
    Vaccine, 2006 May 1;24(18):3750-61.
    PMID: 16102875
    In this paper, we describe the development of VCUSM2, a live metabolic auxotroph of Vibrio cholerae O139. Auxotrophy was achieved by mutating a house keeping gene, hemA, that encodes for glutamyl-tRNA reductase, an important enzyme in the C5 pathway for delta-aminolevulenic acid (ALA) biosynthesis, which renders this strain dependent on exogenous ALA for survival. Experiments using the infant mouse and adult rabbit models show that VCUSM2 is a good colonizer of the small intestine and elicits greater than a four-fold rise in vibriocidal antibodies in vaccinated rabbits. Rabbits vaccinated with VCUSM2 were fully protected against subsequent challenge with 1 x 10(11) CFU of the virulent wild type (WT) strain. Experiments using ligated ileal loops of rabbits show that VCUSM2 is 2.5-fold less toxic at the dose of 1 x 10(6) CFU compared to the WT strain. Shedding of VCUSM2 in rabbits were found to occur for no longer than 4 days and its maximum survival rate in environmental waters is 8 days compared to the greater than 20 days for the WT strain. VCUSM2 is thus a potential vaccine candidate against infection by V. cholerae O139.
  15. Khan TM, Sahibzada MU
    Vaccine, 2016 Apr 19;34(18):2074-81.
    PMID: 26993330 DOI: 10.1016/j.vaccine.2016.03.008
    A qualitative study design was adapted to explore the challenges faced by health workers (HWs) during the polio health campaign. In addition, HWs' opinions about the factors causing parents to refuse oral polio vaccination (OPV) were also explored. Four focus group discussions (FGDs) were held (from 1st January 2015-31st March 2015) with the HWs who participated in the OPV campaigns in the polio red zones of Khyber Pakhtoon Khawa (KPK) province of Pakistan, namely Kohat (FG 1), Domel and Bannu (FG 2), Hangoo (FG 3), and Peshawar (FG 4). A total of N=42 HWs (10-11 in each FG) agreed to participate in this study. Overall, HWs disclosed that public attitude and harsh behaviour towards the HWs and security threats are the two main challenges they face. Common issues hindering parents' willingness to vaccinate their children against OPV are: OPV is seen as haram and not permitted in Islam, it is said to contain the blood of pigs (Khinzir) and monkeys, and parents are afraid that it is done to induce sterility among their children. HWs also shared that parents have a strong belief in the conspiracies that are associated with OPV, i.e. the USA and CIA, are spying on us and our government is helping them to achieve their agenda. Furthermore, HWs revealed that frequent visits may further strengthen parents' perceptions and make them more resistant to OPV. The common side effects of OPV reported by parents were mainly gastro-intestinal problems and in some cases mild to moderate fever with some respiratory symptoms. There is a great need to improve the logistics and facilities for HWs assisting in vaccination programmes. Furthermore, it is necessary to improve education, so people understand the basic concept of revaccination and booster doses, thereby assisting in creating a basic understanding of vaccinations, which may trigger changes in attitudes and make people believe in the benefits of OPV rather than following the conspiracies that lead them to refuse it.
    Matched MeSH terms: Poliovirus Vaccine, Oral/administration & dosage*
  16. Satterfield BA, Dawes BE, Milligan GN
    Vaccine, 2016 06 03;34(26):2971-2975.
    PMID: 26973068 DOI: 10.1016/j.vaccine.2015.12.075
    Nipah virus (NiV) is a highly pathogenic, recently emerged paramyxovirus that has been responsible for sporadic outbreaks of respiratory and encephalitic disease in Southeast Asia. High case fatality rates have also been associated with recent outbreaks in Malaysia and Bangladesh. Although over two billion people currently live in regions in which NiV is endemic or in which the Pteropus fruit bat reservoir is commonly found, there is no approved vaccine to protect against NiV disease. This report examines the feasibility and current efforts to develop a NiV vaccine including potential hurdles for technical and regulatory assessment of candidate vaccines and the likelihood for financing.
  17. Reed Z, Cardosa MJ
    Vaccine, 2016 06 03;34(26):2967-2970.
    PMID: 26973065 DOI: 10.1016/j.vaccine.2016.02.077
    Although outbreaks of Hand, Foot, and Mouth Disease (HFMD) in young children have long been recognized worldwide, the occurrence of rare and life-threatening neurological, respiratory, and cardiac complications has propelled this common condition into the spotlight as a major public health problem in the affected countries. Various enteroviruses cause HFMD, but the severe complications have been mostly associated with enterovirus 71 (EV71). Medical treatment is supportive and measures to interrupt transmission have been challenging to implement. Preventive vaccines could have an important clinical impact, especially among children younger than 3 years old who are most susceptible to the neurological complications. Several groups in the highly affected Asia-Pacific region are working towards vaccines against EV71 and some candidates have progressed to late-stage clinical trials with two vaccines recently reported to have been approved by the regulatory authorities in China. This report summarizes current issues and progress in the development of vaccines against EV71.
  18. Broder CC, Weir DL, Reid PA
    Vaccine, 2016 06 24;34(30):3525-34.
    PMID: 27154393 DOI: 10.1016/j.vaccine.2016.03.075
    Hendra virus (HeV) and Nipah virus (NiV) are zoonotic viruses that emerged in the mid to late 1990s causing disease outbreaks in livestock and people. HeV appeared in Queensland, Australia in 1994 causing a severe respiratory disease in horses along with a human case fatality. NiV emerged a few years later in Malaysia and Singapore in 1998-1999 causing a large outbreak of encephalitis with high mortality in people and also respiratory disease in pigs which served as amplifying hosts. The key pathological elements of HeV and NiV infection in several species of mammals, and also in people, are a severe systemic and often fatal neurologic and/or respiratory disease. In people, both HeV and NiV are also capable of causing relapsed encephalitis following recovery from an acute infection. The known reservoir hosts of HeV and NiV are several species of pteropid fruit bats. Spillovers of HeV into horses continue to occur in Australia and NiV has caused outbreaks in people in Bangladesh and India nearly annually since 2001, making HeV and NiV important transboundary biological threats. NiV in particular possesses several features that underscore its potential as a pandemic threat, including its ability to infect humans directly from natural reservoirs or indirectly from other susceptible animals, along with a capacity of limited human-to-human transmission. Several HeV and NiV animal challenge models have been developed which have facilitated an understanding of pathogenesis and allowed for the successful development of both active and passive immunization countermeasures.
  19. Khan TM, Khan AU, Ali I, Wu DB
    Vaccine, 2016 Mar 8;34(11):1393-8.
    PMID: 26845740 DOI: 10.1016/j.vaccine.2016.01.045
    A cross-sectional study was carried out among HCPs in Northwest General Hospital & Research Centre, Hayatabad Peshawar, Pakistan. The purpose of this study was to investigate knowledge, awareness and attitude of HCPs towards influenza vaccination. A total of N=170 questionnaires were distributed among the staff. There was a 97% response rate to this survey (n=165). The median age of the respondents was 30 years and most of them, 98 (59.0%), were from age group of 24-30 years. The majority of the HCPs that participated in this study were male 106 (64.2%), and by profession, the majority were physicians 77 (46.7%), followed by pharmacists and nurses. A majority 114 (69.1%) believed that it was not compulsory for HCPs to get vaccinated for influenza. Top three identified barriers to vaccination were: not everyone is familiar with the availability of the influenza vaccination at their institution (Relative importance weight factors (RIWF)=0.71), due to needle fear I do not like to get vaccinated (RIWF=0.70) and it is not compulsory for healthcare professionals to get vaccinated for influenza (RIWF=0.64). The logistic regression analysis has revealed association for job experience and profession with the most of the eleven knowledge item. However, when overall sum of eleven items were tested to identify the factors affecting the knowledge score, along with profession (-0.215 [-0.389 to 0.040]; p=0.016) and job experience (0.823 [0.521-1.125]; p<0.001) HCPs age (-0.409 [-0.755 to -0.064]; p=0.020) was found to be another significant factor affecting the total knowledge score of HCPs. Overall, scoring of the correct responses revealed that nurses have better knowledge and understanding about influenza and the influenza vaccination (6.5±0.8, p<0.001*), followed by pharmacists (6.3±1.14) and physicians. In spite of the published guidelines and recommendations, a very low percentage of the healthcare professionals in our hospital were vaccinated against influenza, and the barriers to vaccination were prevalent. Various strategies, including arranging seminars regarding awareness about vaccinations, are required to improve the knowledge and overall outcomes.
  20. Nagendrakumar SB, Hong NT, Geoffrey FT, Jacqueline MM, Andrew D, Michelle G, et al.
    Vaccine, 2015 Aug 26;33(36):4513-9.
    PMID: 26192355 DOI: 10.1016/j.vaccine.2015.07.014
    Pigs play a significant role during outbreaks of foot-and-mouth disease (FMD) due to their ability to amplify the virus. It is therefore essential to determine what role vaccination could play to prevent clinical disease and lower virus excretion into the environment. In this study we investigated the efficacy of the double oil emulsion A Malaysia 97 vaccine (>6PD50/dose) against heterologous challenge with an isolate belonging to the A SEA-97 lineage at 4 and 7 days post vaccination (dpv). In addition, we determined whether physical separation of pigs in the same room could prevent virus transmission. Statistically there was no difference in the level of protection offered by 4 and 7 dpv. However, no clinical disease or viral RNA was detected in the blood of pigs challenged 4 dpv, although three of the pigs had antibodies to the non-structural proteins (NSPs), indicating viral replication. Viral RNA was also detected in nasal and saliva swabs, but on very few occasions. Two of the pigs vaccinated seven days prior to challenge had vesicles distal from the injection site, but on the inoculated foot, and two pigs had viral RNA detected in the blood. One pig sero-converted to the NSPs. In contrast, all unvaccinated and inoculated pigs had evidence of infection. No infection occurred in any of the susceptible pigs in the same room, but separated from the infected pigs, indicating that strict biosecurity measures were sufficient under these experimental conditions to prevent virus transmission. However, viral RNA was detected in the nasal swabs of one group of pigs, but apparently not at sufficient levels to cause clinical disease. Vaccination led to a significant decrease in viral RNA in vaccinated pigs compared to unvaccinated and infected pigs, even with this heterologous challenge, and could therefore be considered as a control option during outbreaks.
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