Human Coronavirus NL63

Burtram C Fielding

Future Microbiol. 2011;6(2):153-159.

Coinfections with Other Respiratory Viruses

Coinfections of HCoV-NL63 and other respiratory viruses, including other HCoVs, influenza A virus, respiratory syncytial virus, parainfluenza virus and human metapneumovirus (hMPV), are common.^{[19,23,27,30,31,43,44,72,73]} Interestingly, coinfected patients are more likely to be hospitalized, indicating the severity of this kind of superinfection.^[74] In a study from Germany, respiratory syncytial virus A and HCoV-NL63 was the most common coinfection identified in children less than 3 years of age. This is probably due to the high incidence of respiratory syncytial virus A in winter and the overlap in the seasonality of the viruses.^[30] Co-infection in hospitalized children with HCoV-NL63 and bocavirus is reported.^[75] The viral load of HCoV-NL63 is lower in coinfected patients than in patients infected with HCoV-NL63 only.^[5,30] The clinical significance of these coinfections are not clear, but various plausible explanations for the lower HCoV-NL63 viral load have previously been discussed: HCoV-NL63 causes the initial infection that weakens the immune system enough for a second viral infection to gain a foothold. By the time this second infection shows symptoms, the HCoV-NL63 infection might have already been brought under control by the host immune system; HCoV-NL63 and the other virus may be in competition for the same cellular receptor or target cell in the respiratory organs; the activation of the innate immune response triggered by the second respiratory virus may cause inhibition of HCoV-NL63; or prolonged persistence of HCoV-NL63 at low levels of expression.^[30,74] Even though these reports may reflect biological complexity or interaction, it is important to keep in mind that virtually all the published studies comprise solely of cohorts of children hospitalized for ARTI and thus are extremely biased.

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Cite this: Human Coronavirus NL63 - Medscape - Feb 01, 2011.

Abstract and Introduction
Prevalence & Seasonal Incidence
Respiratory Clinical Findings
Nonrespiratory Clinical Findings
Coinfections with Other Respiratory Viruses
Future Perspective
Conclusion
References
Sidebar

Table 1. Incidence of HCoV-NL63 in clinical samples.
Country	Method used for detection	Incidence (%; sample size)	Ref.
Australia	RT-PCR	3.30 (234)	[31]
Belgium	RT-PCR	2.30 (309)	[29]
Canada	RT-PCR	3.60 (525)	[18]
France	RT-PCR	9.30 (300)	[25]
Germany	Real-time RT-PCR	5.20 (949)	[28,30]
China	RT-PCR	2.60 (587)	[19]
Italy	RT-PCR	1.86 (150)	[27]
Japan	RT-PCR	1.20 (419)	[24]
Japan	RT-PCR	2.50 (118)	[22]
South Korea	RT-PCR	1.60 (515)	[20]
Taiwan	Quantitative RT-PCR	1.30 (539)	[43]
Thailand	RT-PCR	0.42 (1890)	[44]
South Africa	RT-PCR	8.30 (238)	[26]
Switzerland	RT-PCR	7.00 (82)	[23]
Sweden	RT-PCR	6.00 (212)	[32]
USA	RT-PCR	2.20 (1683)	[21]
South Korea	Multiplex RT-PCR	16.5 (182)	[17]
Germany	Real-time RT-PCR	3.90 (1756)	[5]
Norway	Multiplex real-time PCR	4.50 (536)	[33]

RT-PCR: Reverse transcription PCR.
Modified from [74].

Sidebar

Executive Summary

Prevalence & seasonal incidence

Human coronavirus (HCoV)-NL63 has a worldwide distribution.
HCoV-NL63 infections peak in winter and have an interepidemic period of 2 years.

Respiratory clinical findings

HCoV-NL63 infects both the upper and lower respiratory tracts.
Infection with HCoV-NL63 is often associated with more severe lower respiratory tract infections and subsequent hospitalization.
Lower respiratory tract symptoms include croup and bronchiolitis.

Nonrespiratory clinical findings

The majority of studies did not find an association between HCoV-NL63 infection and Kawasaki disease.
HCoV-NL63 has been detected in a small number of diarrhea stool samples.

Coinfections with other respiratory viruses

Coinfections with other well known respiratory viruses are very common.
HCoV-NL63 viral load is higher in patients infected with HCoV-NL63 alone.
Patients with coinfections are more likely to be hospitalized.

Future perspective

More comprehensive population-based studies are needed to determine the involvement of HCoV-NL63 in the infection of systems other than the respiratory tract.
The development of the HCoV-NL63 infectious clone will greatly aid in understanding this virus.
An animal model is required for virus study and vaccine development.

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Human Coronavirus NL63

Coinfections with Other Respiratory Viruses

Tables

References

Authors and Disclosures

Authors and Disclosures

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Sidebar

Executive Summary

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