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J C de Jong

Publications and source records attributed to J C de Jong.

At least 19 recordsLinked to original sources
PubMed2006

[The 2005-2006 influenza season in the Netherlands and the vaccine composition for the 2006-2007 season].

The first sign of influenza activity in the Netherlands during the 2005-2006 influenza season was the isolation of influenza viruses in the last week of 2005. From Week 1 of 2006 onwards, an increase in clinical influenza activity was also observed that did not return to baseline levels until Week 15. Two waves of influenza activity were observed with peak incidences of 13.8 and 9.8 influenza-like illnesses per 10,000 inhabitants on Weeks 7 and 12, respectively. The first wave of influenza was caused primarily by influenza B viruses, whereas the second wave was caused predominantly by influenza A/H3N2 viruses. The influenza B viruses appeared to belong to two different phylogenetic lineages and were antigenically distinguishable from the vaccine strain. The isolated influenza A/H3N2 viruses were closely related to the vaccine strain for this subtype and only minor antigenic differences with the vaccine strain were observed for a limited number of isolates. Only a small number of influenza A/H1N1 viruses were isolated, which all closely resembled the H1N1 vaccine strain. For the 2006-2007 influenza season, the World Health Organization has recommended the following vaccine composition: A/Wisconsin/67/05 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Malaysia/2506/05.

Disease Outbreaks↗
PubMed2005

[The influenza season 2004/'05 in the Netherlands with the largest epidemic of the last 5 years caused by the virus variant A/California and the composition of the vaccine for the season 2005/'06].

In the Netherlands, the influenza epidemic of the 2004/'05 season started late. The background value of 3 cases of an influenza-like illness per 10,000 inhabitants per week was exceeded from week 1 until week 14 of 2005. The magnitude of the epidemic was the largest of the last 5 years, namely 104 per 10,000 inhabitants. As usual, the epidemic was caused mainly by influenza-A viruses of subtype H3N2 and to a lesser degree by A/H1N1 and B viruses. The H3N2-virus isolates belonged to the newly emerged variant A/California/7/04, which deviated slightly from the vaccine strain used for the 2004/'05 season. The influenza-B and H1N1 viruses matched the corresponding vaccine viruses well. For the 2005/'06 season, the World Health Organization has recommended the following vaccine composition: A/California/7/04 (H3N2), A/New Caledonia/20/99 (HiNI), and B/Shanghai/361/02.

Global Health↗
PubMed2004

[The 2003/2004 influenza season in the Netherlands with a limited epidemic of the virus variant A/Fujian, and the vaccine composition for the 2004/2005 season].

In contrast to the three previous influenza seasons, the influenza epidemic of the 2003/2004 season started early in week 49 of 2003. The epidemic was predominantly caused by influenza-A viruses of the H3N2 subtype. All isolated influenza-A viruses were antigenically related to influenza virus A/Fujian/411/02, which was already detected in the influenza season 2002/2003 and that deviated from the vaccine-reference strain A/Moscow/10/99 to a certain extent. The magnitude of the epidemic was limited despite the fact that it was caused by influenza-A H3N2-virus-drift variants. Immunity caused by natural infection with influenza viruses during previous seasons or vaccination has possibly provided sufficient cross protection against these new H3N2-drift variant. No influenza-A viruses of the H1N1 or H1N2 subtypes were detected in the influenza season 2003/2004. Only a small number of influenza-B viruses were isolated, which all belonged to the B/Yamagata/16/88 lineage, which was temporarily replaced by the B/Victoria2/87 lineage in the previous influenza season. On the basis of epidemiological and serological data the World Health Organization has recommended the following vaccine composition for the 2004/2005 influenza season: A/Fujian/411/02 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Shanghai/361/02.

Global Health↗
PubMed2004

[Neuraminidase inhibitors oseltamivir and zanamivir: new means of defence against influenza].

Recently two new neuraminidase inhibitors zanamivir and oseltamivir have been marketed. They appear to considerably reduce morbidity and mortality from influenza. Their adverse effects are infrequent and mild and the chance of development of pathogenically significant resistant mutants appears to be small. During the first six months of a pandemic, neuraminidase inhibitors are the only defence against the virus. It is therefore important to stockpile in each country sufficient quantities of these drugs. During the usual influenza epidemics the main value of neuraminidase inhibitors lies in their use for therapy, prophylaxis and post-exposure prophylaxis in long-term care institutions for the elderly (for prophylaxis only oseltamivir is licensed). Although data on the effectiveness against complications of influenza and on the effect on people with an increased risk of (fatal) complications as a result of an influenza virus infection are limited, the available information on the effects of the neuraminidinase inhibitors indicates that these drugs will also protect against complications and that high-risk groups will benefit from the rapid deployment of these products. The cost-effectiveness of treatment and post-exposure prophylaxis with neuraminidinase inhibitors is probably not favourable for healthy children and adults but seems to be favourable for the high-risk groups (vaccinated or not) in winter.

Acetamides↗
PubMed2003

[The 2002/2003 influenza season in the Netherlands and the vaccine composition for the 2003/2004 season].

As in the 2000/2001 and 2001/2002 seasons, the influenza epidemic in the 2002/2003 season started late (week 7 of 2003) and was only moderate in size. Influenza A (H3N2) and B viruses were detected in equal numbers among patients of general practitioners and these two viruses were therefore equally responsible for the epidemic. However, H3N2 viruses dominated isolates taken from hospitals. In haemagglutination-inhibition (HI) assays most of the H3N2 viruses proved highly reactive with antiserum to the vaccine-reference strain A/Moscow/10/99. This was also true for a number of isolates, including those obtained from nursing home residents, closely related to the reference strain A/Finland/170/03. However, an estimated 4% of the H3N2 isolates belonged to the variant A/Fujian/411/02 from China, which constituted the majority of the H3N2 viruses isolated in Europe in the later phase of the season. This variant reacted poorly with antiserum to A/Moscow/10/99. In H1 tests all influenza A(H1N1)-virus isolates and all B-virus isolates were closelyrelated to the corresponding vaccine-reference strains. Taking this data into consideration, the World Health Organization has advised the same vaccine composition for the 2003/2004 season as for the 2002/2003 season, namely: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Hong Kong/330/01. There is the possibility of a mismatch occurring between the H3N2-vaccine strain and the circulating H3N2 viruses in the coming influenza season. In March and April 2003 there was an outbreak of influenza-A (H7N7) fowl plague in the Netherlands. A special monitoring survey revealed that 91 people who had handled infected poultry became infected with the H7N7 virus. One of these later died as a result of this. None of the avian and human H7N7-virus isolates examined contained human or porcine influenza-A virus genes.

Global Health↗
PubMed2003

Haemagglutination-inhibiting antibody to influenza virus.

The results of the haemagglutination-inhibiting (HI) antibody test for influenza virus antibody in human sera closely match those produced by virus neutralization assays and are predictive of protection. On the basis of the data derived from 12 publications concerning healthy adults, we estimated the median HI titre protecting 50% of the vaccinees against the virus concerned at 28. This finding supports the current policy requiring vaccines to induce serum HI titres of > or = 40 to the vaccine viruses in the majority of the vaccinees. Unfortunately similar studies are scanty for the elderly, the group most at risk of influenza. There still remain many unsolved technical problems with the HI assay and we recommend that these problems be studied and the virus neutralization test as a predictor of resistance to influenza be assessed. Although the studies on this issue often give conflicting results, they generally show that HI antibody responses to influenza vaccination tend to diminish with increasing age, when health is often compromized. Advanced age in itself seems not to be an independent factor in this process. However, even in completely healthy elderly individuals the response to vaccination with an antigenically new virus may be strongly reduced compared with younger vaccinees.

Antibodies, Viral↗
PubMed2002

[The 2001/2002 influenza season and the vaccine composition for the 2002/2003 season].

The epidemic in the influenza season 2001/2002 was of moderate activity just like in 2000/2001. The influenza epidemic started in week 2 of 2002 when the clinical influenza activity reported by the general practitioner network of the Netherlands Institute of Primary Health Care (NIVEL) increased. This was caused by influenza A viruses of the H3N2 subtype in particular. All influenza A viruses of this subtype were closely related to the vaccine strain for this subtype, A/Moscow/10/99. Influenza B viruses and influenza A/H1 viruses isolated this season had surprising features. The influenza B viruses originated from two lineages. Viruses of the B/Yamagata/16/88 lineage have been circulating for more than twelve years. The vaccine reference strain B/Sichuan/379/99 belongs to this lineage. The B/Victoria/2/87 lineage reappeared again after an absence in Europe of more than ten years and accounted for 50% of the influenza B viruses that were isolated in the Netherlands. Therefore the vaccine will have provided only partial protection against influenza B. The only influenza A/H1 virus that was isolated appeared to be of a new subtype H1N2. The H1 hemagglutinin of this virus was closely related to that of the vaccine strain A/New Caledonia/20/99. The N2 neuraminidase originated from recent human influenza A/H3N2 viruses. Therefore the vaccine probably provided good protection against the new H1N2 subtype. Based in part on these data, the World Health Organization has advised that the vaccines for the season 2002/2003 should contain the following or comparable influenza-virus strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Hong Kong/330/01, the latter being an influenza B virus of the B/Victoria/2/87 lineage.

Global Health↗
PubMed2002

H5N1 influenza in Hong Kong: virus characterizations.

In 1997, 18 people were infected in Hong Kong with an avian influenza A(H5N1) virus from chicken. This type of interspecies transmission was never detected before and could have resulted in the development of a pandemic strain. The occurrence suggests that the pig is not needed for the emergence of pandemic influenza virus strains. Characteristics of the strains involved are discussed in relation to the question why, on the one hand, these strains were able to infect humans but on the other hand were not able to start an epidemic.

Amino Acid Sequence↗
PubMed2002

Cold-adapted live influenza vaccine versus inactivated vaccine: systemic vaccine reactions, local and systemic antibody response, and vaccine efficacy. A meta-analysis.

Since the 1940s, influenza vaccines are inactivated and purified virus or virus subunit preparations (IIV) administered by the intramuscular route. Since decades, attempts have been made to construct, as an alternative, attenuated live influenza vaccines (LIV) for intranasal administration. Presently, the most successful LIV is derived from the cold-adapted master strains A/Ann Arbor/6/60 (H2N2) and B/Ann Arbor/1/66 (AA-LIV, for Ann-Arbor-derived live influenza vaccine). It has been claimed that AA-LIV is more efficacious than IIV. In order to assess differences between the two vaccines with respect to systemic reactogenicity, antibody response, and efficacy, we performed a meta-analysis on eighteen randomised comparative clinical trials involving a total of 5000 vaccinees of all ages. Pooled odds ratios (AA-LIV versus IIV) were calculated according to the random effects model. The two vaccines were associated with similarly low frequencies of systemic vaccine reactions (pooled odds ratio: 0.96, 95% confidence interval: 0.74-1.24). AA-LIV induced significantly lower levels of serum haemagglutination inhibiting antibody and significantly greater levels of local IgA antibody (influenza virus-specific respiratory IgA assayed by ELISA in nasal wash specimens) than IIV. Yet, although they predominantly stimulate different antibody compartments, the two vaccines were similarly efficacious in preventing culture-positive influenza illness. In all trials assessing clinical efficacy, the odds ratios were not significantly different from one (point of equivalence). The pooled odds ratio for influenza A-H3N2 was 1.50 (95% CI: 0.80-2.82), and for A-H1N1, 1.03 (95% CI: 0.58-1.82). The choice between the two vaccine types should be based on weighing the advantage of the attractive non-invasive mode of administration of AA-LIV, against serious concerns about the biological risks inherent to large-scale use of infectious influenza virus, in particular the hazard of gene reassortment with non-human influenza virus strains.

Adaptation, Physiological↗
PubMed2001

[2000/01 influenza season and the vaccine composition for the season 2001/'02].

In the 2000/01 season, the size of the influenza epidemic in the Netherlands was exceptionally small. Since the start of the Continuous Morbidity Registration of the Netherlands Institute of Primary Health Care (NIVEL) in 1970, the peak incidence of influenza-like illnesses has never been so low. The aetiology of the epidemic was also unusual. Most remarkable was the relatively extensive circulation of subtype H1N1 and the low activity of subtype H3N2. The epidemic started in week 1 of 2001 and ended in week 8. The antigenic properties of the influenza A (H1N1) viruses closely resembled those of the vaccine strain A/New Caledonia/20/99. This new variant of subtype H1N1 was first isolated in Asia in 1995 and was only (sporadically) detected in the Netherlands in the 1999/2000 season. Phylogenetic analysis showed that these viruses represent a new line of subtype H1N1. Following the influenza-activity caused by H1N1 viruses in the 2000/01 season, a small number of B and H3N2 viruses were also isolated up to week 19. Antigenically, these viruses were identical to those obtained in the previous years. On the basis of the antigenetic analyses presented, it can be concluded that the vaccine provided good protection against the circulating influenza viruses in the 2000/01 season. The World Health Organization recommends that influenza vaccines intended for use in the 2001/02 season of the northern hemisphere should contain the following, or antigenically similar, strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1), and B/Sichuan/379/99.

Global Health↗
PubMed2001

Antigenic and molecular heterogeneity in recent swine influenza A(H1N1) virus isolates with possible implications for vaccination policy.

In order to explore the occurrence of antigenic drift in swine influenza A(H1N1) viruses and the match between epidemic and vaccine strains, 26 virus isolates from outbreaks of respiratory disease among finishing pigs in the Netherlands in the 1995/1996 season and reference strains from earlier outbreaks were examined using serological and molecular methods. In contrast to swine H3N2 viruses, no significant antigenic drift was observed in swine H1N1 viruses isolated from the late 1980s up to 1996 inclusive. However, a marked antigenic and genetic heterogeneity in haemagglutination inhibition tests and nucleotide sequence analyses was detected among the 26 recent swine H1N1 virus strains. Interestingly, the observed antigenic and molecular variants were not randomly distributed over the farms. This finding indicates independent introductions of different swine H1N1 virus variants at the various farms of the study and points to a marked difference between the epidemiologies of human and swine influenza viruses. The observed heterogeneity may hamper the control of swine influenza by vaccination and indicates that the efficacy of current swine influenza vaccines requires re-evaluation and that the antigenic reactivity of swine influenza viruses should be monitored on a regular basis.

Animals↗
PubMed2001

Antigenic and genetic characterization of swine influenza A (H1N1) viruses isolated from pneumonia patients in The Netherlands.

It is generally believed that pigs can serve as an intermediate host for the transmission of avian influenza viruses to humans or as mixing vessels for the generation of avian-human reassortant viruses. Here we describe the antigenic and genetic characterization of two influenza A (H1N1) viruses, which were isolated in The Netherlands from two patients who suffered from pneumonia. Both viruses proved to be antigenically and genetically similar to avian-like swine influenza A (H1N1) viruses which currently circulate in European pigs. It is concluded that European swine H1N1 viruses can infect humans directly, causing serious disease without the need for any reassortment event.

Adult↗
PubMed2001

A newly discovered human pneumovirus isolated from young children with respiratory tract disease.

From 28 young children in the Netherlands, we isolated a paramyxovirus that was identified as a tentative new member of the Metapneumovirus genus based on virological data, sequence homology and gene constellation. Previously, avian pneumovirus was the sole member of this recently assigned genus, hence the provisional name for the newly discovered virus: human metapneumovirus. The clinical symptoms of the children from whom the virus was isolated were similar to those caused by human respiratory syncytial virus infection, ranging from upper respiratory tract disease to severe bronchiolitis and pneumonia. Serological studies showed that by the age of five years, virtually all children in the Netherlands have been exposed to human metapneumovirus and that the virus has been circulating in humans for at least 50 years.

Adolescent↗
PubMed2000

[Influenza season 1999/2000 and vaccine composition for the season 2000/01].

The first signs of influenza activity in the Netherlands during the 1999/2000 influenza season were the isolation of an influenza A (H3N2) virus in week 40 and of two more in week 43 of 1999. From week 50 onwards, a strong increase of the clinical influenza activity was observed which reached its peak in weeks 1 and 2 of 2000 and then rapidly declined. The clinical influenza activity was associated with the isolation of predominantly influenza A (H3N2) viruses. Near the end of the epidemic, influenza A (H1N1) and influenza B viruses were isolated sporadically. The antigenic properties of the influenza A (H3N2) viruses resembled those of the epidemic strains isolated in the previous season and the vaccine strain A/Sydney/5/97. This influenza season, influenza B viruses did not play a significant role and they matched the vaccine strain B/Yamanashi/166/98. In addition, a small number of influenza A (H1N1) viruses were isolated. Some of these viruses resembled the old variant of influenza A (H1N1) viruses, A/Bayern/7/95, whilst others showed a close antigenic relationship with the vaccine strain recommended for the next influenza season, A/New Caledonia/20/99. For the influenza season 2000/'01, it is recommended by the World Health Organization that the vaccines contain the following (or similar) virus strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Beijing/184/93.

Disease Outbreaks↗