Expert Review of Vaccines Downloaded from informahealthcare.com by Nyu Medical Center on 06/23/15 For personal use only.
Review
The potential impact of climate change and ultraviolet radiation on vaccine-preventable infectious diseases and immunization service delivery system Expert Rev. Vaccines 14(4), 561–577 (2015)
Biao Guo*, Suchithra Naish, Wenbiao Hu and Shilu Tong Queensland University of Technology, School of Public Health and Social Work, D Wing, O Block, Victoria Park Road, Kelvin Grove, Brisbane, 4059, Australia *Author for correspondence: [email protected]
Climate change and solar ultraviolet radiation may affect vaccine-preventable infectious diseases (VPID), the human immune response process and the immunization service delivery system. We systematically reviewed the scientific literature and identified 37 relevant publications. Our study shows that climate variability and ultraviolet radiation may potentially affect VPID and the immunization delivery system through modulating vector reproduction and vaccination effectiveness, possibly influencing human immune response systems to the vaccination, and disturbing immunization service delivery. Further research is needed to determine these affects on climate-sensitive VPID and on human immune response to common vaccines. Such research will facilitate the development and delivery of optimal vaccination programs for target populations, to meet the goal of disease control and elimination. KEYWORDS: climate variability . immunization service . infectious disease . ultraviolet radiation . vaccine
Climate change is increasingly recognized as one of the greatest global health threats of the 21st century [1,2]; climate change poses a wide range of, both directly and indirectly, adverse effects on human health [3]. Recognized direct impacts include injury, death, post-event traumatic stress and disease risk due to amplified extreme weather events; while indirect impacts include the increased risks of infectious diseases, poor nutrition status, unhygienic food and depression mediated by the primary environmental and social impacts of climate change [1]. The consequences of climate change such as the sea level rise and changes in temperature, humidity and rainfall may influence the transmission dynamics of infectious diseases [3].
informahealthcare.com
10.1586/14760584.2014.990387
Solar ultraviolet radiation (UVR) may also influence health. Ozone (O3) exists in two layers of atmosphere: the troposphere and the stratosphere. In the troposphere, the closest layer to the earth, O3 is noxious pollutant and exposure is associated with respiratory problems [4]. UVR can be divided into UVC (200–280 nm), UVB (280–315 nm) and UVA (315–400 nm) based on various wavelengths [5]. Hundred percent UVC and over 90% UVB are absorbed in the stratosphere [3]. In contrast to the troposphere, O3 in the stratosphere functions as a shield, protecting the earth and humans from excess exposure to UVB [4]. Depletion of stratospheric O3 has been considered as one of the most important environmental threats [6]. This has been recognized as far
2014 Informa UK Ltd
ISSN 1476-0584
561
Review
Guo, Naish, Hu & Tong
Figure 1. Flow chart of selection criteria of included/excluded studies.
herd immunity. Over the past 40 years, Expanded Program on Immunization has reached over 80% of children under 1 year and averts two to three million deaths from diphtheria, tetanus, pertussis and measles annually [22]. WHO aims to expand the vaccination programs with the continued development of vaccination programs and licensing of vaccines [21]. The effectiveness and sustainability of the national immunization programs is, however, associated with a series of changes in socio-economic and environmental factors. Most vaccinepreventable infectious diseases (VPID) targeted by the national immunization programs are mosquito-borne diseases, air-borne diseases, water- and food-borne diseases and blood-borne diseases. Target diseases, however, vary by country. Successful implementation of national immunization program requires safe and effective vaccines eliciting human immune response and a reliable immunization service delivery system, which may be influenced by climatic variability and changes. Climate variability refers to ‘variations in the mean state and other statistics (such as standard deviations, the occurrence of extremes, etc.) of the climate on all temporal and spatial scales beyond that of individual weather events’ occurring over a given period of time; climate change refers to ‘a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer)’ [23]. The potential impact of climate change on the immunization delivery systems has rarely been considered. This paper reviews the impact of climate change and UVR exposure on VPID and the immunization delivery systems, identifies knowledge gaps, and finally, recommends future research directions.
back as 1987 with the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer, which was designed to reduce the production and consumption of ozone-depleting substances in order to reduce their abundance in the atmosphere, and thus protect the earth’s fragile ozone layer [7]. Between 1979 and 2008, depletion of stratospheric ozone has occurred at the pole in the Antarctic region resulting in over 30 O3 holes [8]. In 2011, a hole was recorded for the first time in the ozone layer above the Arctic [9]. Depletion of stratospheric ozone has led to excessive UVB exposure in recent decades, which is associated with health risks [6] including: melanoma [10–13], non-melanoma skin cancers (basal cell carcinoma [14–16], squamous cell carcinoma [17]), Merkel cell carcinoma [10] and common eye diseases [18,19]. Vaccination is recognized as one of the greatest public health achievements of the 20th century [20]. The objectives of the WHO vaccination programs have evolved from vaccinating children throughout the world in its Expanded Program on Immunization launched in 1974, to vaccinate all people by 2020 in the Global Vaccine Action Plan (GVAP), in order to achieve the visionary goal of a world in which all individuals and communities enjoy lives free from vaccine-preventable diseases [21]. In general, to protect each individual against various diseases, routine immunization and supplementary immunization strategies have been applied in each country to achieve the
Methods A comprehensive literature search on the impacts of climate change and UVR exposure on VPID and the immunization delivery systems was conducted in March 2014. We retrieved all the relevant articles published between January 1980 and March 2014. Searches were performed on Ebscohost, Scopus, PubMed Central, Cochrane library, Embase and Google Scholar using the keywords and MeSH terms (‘climate’ or ‘climate change’ or ‘seasonality’ or ‘ultra violet*’) and (‘vaccine’ or ‘adverse event*’ or ‘immu*’ or ‘infection/s’ or ‘infectious disease/s’). A total of 3309 publications were identified. These were narrowed down using the following selection criteria. For inclusion, papers were required to be: peer-reviewed journal articles published in English; an assessment of the relationship between VPID and climate variability or climate change, or the relationship between VPID and UVR, or the relationship between human immune system and UVR and a study with clear epidemiological study design. FIGURE 1 shows the flowchart of selection criteria for the inclusion/exclusion of peer-reviewed journal articles in this analysis. We selected 37 relevant studies meeting the selection criteria based on screening of title, abstract and full text, which included additional 25 studies identified in the reference list of the identified articles. A detailed summary of the included studies is presented in (TABLE 1).
Papers identified through database searching (n = 3284)
Additional papers identified through other sources (n = 25)
Expert Review of Vaccines Downloaded from informahealthcare.com by Nyu Medical Center on 06/23/15 For personal use only.
Papers screened (n = 3309) Papers excluded, with reasons (n = 3204): Duplicate records; Reviews, letters or commentaries; Non-english studies; Non-human studies Full-text articles assessed for eligibility Full-text articles excluded, if not focusing on the associations between (n = 68): climate and vaccine preventable infectious diseases; Ultraviolet radiation and health Studies included for review (n = 37)
562
Expert Rev. Vaccines 14(4), (2015)
informahealthcare.com
November 2008–October 2009
January 2006– December 2010
1970–2011
2005–2011
2010
1975–2008
Silva et al. (2013)
Mahamat et al. (2013)
Beest et al. (2013)
Yu et al. (2013)
Li et al. (2013)
Tamerius et al. (2013)
Time-series analysis
French Guiana
78 countries
China, Zhuhai
China (30 provinces)
Crosssectional analysis
Crosssectional analysis
Spatiotemporal analysis
Time-series analysis
Time-series analysis
Brazil (Porto Alegre city)
The Netherlands
Descriptive
Study design
China (Changsha city)
Country (region)
(–) (+) (–) (+) (+)
Temperature Specific humidity Solar radiation Precipitation Relative humidity
Influenza (exl. A/H1N1)†
(++)
Relative humidity
Influenza B
(+)
Temperature
(–)
Sunshine duration Influenza A (H3N2)†
(–)
Minimum temperature
Influenza A and B
(––)
Absolute humidity
(++)
(++)
Sunshine duration
Specific humidity
(––)
Relative humidity
(++)
(++)
Mean temperature
Rainfall
(–)
(+)
Barometric pressure >1010
Sunshine duration
(+)
Average wind speed
Review
The potential impact of climate change and ultraviolet radiation on vaccine-preventable infectious diseases and immunization service delivery system Expert Rev. Vaccines 14(4), 561–577 (2015)
Biao Guo*, Suchithra Naish, Wenbiao Hu and Shilu Tong Queensland University of Technology, School of Public Health and Social Work, D Wing, O Block, Victoria Park Road, Kelvin Grove, Brisbane, 4059, Australia *Author for correspondence: [email protected]
Climate change and solar ultraviolet radiation may affect vaccine-preventable infectious diseases (VPID), the human immune response process and the immunization service delivery system. We systematically reviewed the scientific literature and identified 37 relevant publications. Our study shows that climate variability and ultraviolet radiation may potentially affect VPID and the immunization delivery system through modulating vector reproduction and vaccination effectiveness, possibly influencing human immune response systems to the vaccination, and disturbing immunization service delivery. Further research is needed to determine these affects on climate-sensitive VPID and on human immune response to common vaccines. Such research will facilitate the development and delivery of optimal vaccination programs for target populations, to meet the goal of disease control and elimination. KEYWORDS: climate variability . immunization service . infectious disease . ultraviolet radiation . vaccine
Climate change is increasingly recognized as one of the greatest global health threats of the 21st century [1,2]; climate change poses a wide range of, both directly and indirectly, adverse effects on human health [3]. Recognized direct impacts include injury, death, post-event traumatic stress and disease risk due to amplified extreme weather events; while indirect impacts include the increased risks of infectious diseases, poor nutrition status, unhygienic food and depression mediated by the primary environmental and social impacts of climate change [1]. The consequences of climate change such as the sea level rise and changes in temperature, humidity and rainfall may influence the transmission dynamics of infectious diseases [3].
informahealthcare.com
10.1586/14760584.2014.990387
Solar ultraviolet radiation (UVR) may also influence health. Ozone (O3) exists in two layers of atmosphere: the troposphere and the stratosphere. In the troposphere, the closest layer to the earth, O3 is noxious pollutant and exposure is associated with respiratory problems [4]. UVR can be divided into UVC (200–280 nm), UVB (280–315 nm) and UVA (315–400 nm) based on various wavelengths [5]. Hundred percent UVC and over 90% UVB are absorbed in the stratosphere [3]. In contrast to the troposphere, O3 in the stratosphere functions as a shield, protecting the earth and humans from excess exposure to UVB [4]. Depletion of stratospheric O3 has been considered as one of the most important environmental threats [6]. This has been recognized as far
2014 Informa UK Ltd
ISSN 1476-0584
561
Review
Guo, Naish, Hu & Tong
Figure 1. Flow chart of selection criteria of included/excluded studies.
herd immunity. Over the past 40 years, Expanded Program on Immunization has reached over 80% of children under 1 year and averts two to three million deaths from diphtheria, tetanus, pertussis and measles annually [22]. WHO aims to expand the vaccination programs with the continued development of vaccination programs and licensing of vaccines [21]. The effectiveness and sustainability of the national immunization programs is, however, associated with a series of changes in socio-economic and environmental factors. Most vaccinepreventable infectious diseases (VPID) targeted by the national immunization programs are mosquito-borne diseases, air-borne diseases, water- and food-borne diseases and blood-borne diseases. Target diseases, however, vary by country. Successful implementation of national immunization program requires safe and effective vaccines eliciting human immune response and a reliable immunization service delivery system, which may be influenced by climatic variability and changes. Climate variability refers to ‘variations in the mean state and other statistics (such as standard deviations, the occurrence of extremes, etc.) of the climate on all temporal and spatial scales beyond that of individual weather events’ occurring over a given period of time; climate change refers to ‘a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer)’ [23]. The potential impact of climate change on the immunization delivery systems has rarely been considered. This paper reviews the impact of climate change and UVR exposure on VPID and the immunization delivery systems, identifies knowledge gaps, and finally, recommends future research directions.
back as 1987 with the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer, which was designed to reduce the production and consumption of ozone-depleting substances in order to reduce their abundance in the atmosphere, and thus protect the earth’s fragile ozone layer [7]. Between 1979 and 2008, depletion of stratospheric ozone has occurred at the pole in the Antarctic region resulting in over 30 O3 holes [8]. In 2011, a hole was recorded for the first time in the ozone layer above the Arctic [9]. Depletion of stratospheric ozone has led to excessive UVB exposure in recent decades, which is associated with health risks [6] including: melanoma [10–13], non-melanoma skin cancers (basal cell carcinoma [14–16], squamous cell carcinoma [17]), Merkel cell carcinoma [10] and common eye diseases [18,19]. Vaccination is recognized as one of the greatest public health achievements of the 20th century [20]. The objectives of the WHO vaccination programs have evolved from vaccinating children throughout the world in its Expanded Program on Immunization launched in 1974, to vaccinate all people by 2020 in the Global Vaccine Action Plan (GVAP), in order to achieve the visionary goal of a world in which all individuals and communities enjoy lives free from vaccine-preventable diseases [21]. In general, to protect each individual against various diseases, routine immunization and supplementary immunization strategies have been applied in each country to achieve the
Methods A comprehensive literature search on the impacts of climate change and UVR exposure on VPID and the immunization delivery systems was conducted in March 2014. We retrieved all the relevant articles published between January 1980 and March 2014. Searches were performed on Ebscohost, Scopus, PubMed Central, Cochrane library, Embase and Google Scholar using the keywords and MeSH terms (‘climate’ or ‘climate change’ or ‘seasonality’ or ‘ultra violet*’) and (‘vaccine’ or ‘adverse event*’ or ‘immu*’ or ‘infection/s’ or ‘infectious disease/s’). A total of 3309 publications were identified. These were narrowed down using the following selection criteria. For inclusion, papers were required to be: peer-reviewed journal articles published in English; an assessment of the relationship between VPID and climate variability or climate change, or the relationship between VPID and UVR, or the relationship between human immune system and UVR and a study with clear epidemiological study design. FIGURE 1 shows the flowchart of selection criteria for the inclusion/exclusion of peer-reviewed journal articles in this analysis. We selected 37 relevant studies meeting the selection criteria based on screening of title, abstract and full text, which included additional 25 studies identified in the reference list of the identified articles. A detailed summary of the included studies is presented in (TABLE 1).
Papers identified through database searching (n = 3284)
Additional papers identified through other sources (n = 25)
Expert Review of Vaccines Downloaded from informahealthcare.com by Nyu Medical Center on 06/23/15 For personal use only.
Papers screened (n = 3309) Papers excluded, with reasons (n = 3204): Duplicate records; Reviews, letters or commentaries; Non-english studies; Non-human studies Full-text articles assessed for eligibility Full-text articles excluded, if not focusing on the associations between (n = 68): climate and vaccine preventable infectious diseases; Ultraviolet radiation and health Studies included for review (n = 37)
562
Expert Rev. Vaccines 14(4), (2015)
informahealthcare.com
November 2008–October 2009
January 2006– December 2010
1970–2011
2005–2011
2010
1975–2008
Silva et al. (2013)
Mahamat et al. (2013)
Beest et al. (2013)
Yu et al. (2013)
Li et al. (2013)
Tamerius et al. (2013)
Time-series analysis
French Guiana
78 countries
China, Zhuhai
China (30 provinces)
Crosssectional analysis
Crosssectional analysis
Spatiotemporal analysis
Time-series analysis
Time-series analysis
Brazil (Porto Alegre city)
The Netherlands
Descriptive
Study design
China (Changsha city)
Country (region)
(–) (+) (–) (+) (+)
Temperature Specific humidity Solar radiation Precipitation Relative humidity
Influenza (exl. A/H1N1)†
(++)
Relative humidity
Influenza B
(+)
Temperature
(–)
Sunshine duration Influenza A (H3N2)†
(–)
Minimum temperature
Influenza A and B
(––)
Absolute humidity
(++)
(++)
Sunshine duration
Specific humidity
(––)
Relative humidity
(++)
(++)
Mean temperature
Rainfall
(–)
(+)
Barometric pressure >1010
Sunshine duration
(+)
Average wind speed
