Tuesday, July 16, 2024

Infectious diseases and vaccine sciences

What does the Programme do?
ICDDR,B is a vibrant institution with various experts actively engaged in research on infectious diseases. Microbiologists conduct fundamental research on the characteristics of pathogens. Immunologists study host defences, including potential vaccine candidates. Clinical scientists study the diseases caused by these infectious agents and evaluate optimum therapy in infected patients. Epidemiologists study the magnitude, distribution, risk factors, and effectiveness of preventive interventions for these infections. Anthropologists study the understanding of these diseases in communities and their impact on daily life. Health economists consider the burden caused by these diseases and the coping strategies used for addressing them. Health systems experts evaluate the health-system response to infectious diseases.
One advantage of the research environment at ICDDR,B is that there are a critical mass of scientists from a number of disciplines working on infectious diseases. The Programme on Infectious Diseases and Vaccine Sciences supports and encourages collaboration across all the scientific divisions within ICDDR,B on infectious disease research. The Programme’s research priorities include understanding the causes, distribution, and control of key infectious diseases, responding to disease outbreaks, and evaluating promising vaccines. This collaboration allows multi-disciplinary teams to address problems with greater synergy and productivity than single disciplinary work allows.
2006 Highlights
ICDDR,B research on rotavirus
In 2006, the work on rotavirus by various researchers throughout the Centre illustrates the type of cross-disciplinary work that is central to the Programme on Infectious Diseases and Vaccine Sciences.
One of the most exciting achievements in global public health in 2006 was the publication of results of two large trials of two different vaccines against rotavirus. Rotavirus is estimated to cause 600,000 childhood deaths each year. The live rotavirus vaccine- RotaRix- developed by Glaxo Smith Kline, was 85% effective in preventing severe disease due to rotavirus. The Rota Teq vaccine, developed by Merck & Company~ was 98% effective in preventing severe disease due to rotavirus in the first year and 88% in the second year. These two papers were selected by The Lancet as the “Paper of the Year.” The Lancet editors opined that these two vaccines one day are likely to stand alongside smallpox, measles, and poliomyelitis vaccines in their global public health benefit” [Butcher J. Paper of the Year 2006. Lancet 2007;369:91-2].
These studies represent important advances, although a number of questions remained unanswered regarding rotavirus vaccine in Bangladesh and in other high-need countries. The vast majority of children enrolled in two rotavirus studies were residents of the United States, Western Europe, and Latin America. Numerous previous rotavirus vaccine candidates have shown good efficacy in some countries and poor efficacy in others. Live enteric virus vaccines have characteristically performed much worse in South Asia and other settings with high prevalence of malnutrition, diarrhoeal diseases, and poor sanitation.
To determine the appropriateness of rotavirus vaccine for Bangladesh, two questions are central. First, how much disease from rotavirus is present in Bangladesh? Second, when introduced into the local population, how effective will the new vaccines be against the strains of rotavirus circulating in Bangladesh in preventing severe disease due to rotavirus?
Burden of rotavirus-associated disease in Bangladesh
ICDDR,B scientists made substantial progress in addressing both of the above questions in 2006. Since 1993, ICDDR,B h~ maintainined a surveillance for determining the causes of diarrhoea among patients visiting the Dhaka and Matlab hospitals. Epidemiologists in the Health Systems and Infections Diseases Division collaborated with clinical scientists in the Clinical Sciences Division, along with collaborators from the Centers for Disease Control and Prevention and Emory University, USA.
They reviewed the surveillance data and extracted the proportion of children aged below 5 years hospitalized for diarrhoea with rotavirus identified in their stools at the two ICDDR,B hospitals. They used this proportion as an estimate of the proportion of children, with severe diarrhoea, who have rotavirus, throughout the country. Next, they reviewed the data from the most recent Bangladesh Demographic and Health Survey to estimate the rate of death from diarrhoea among children in Bangladesh. They applied the proportion of cases attributed to rotavirus in the hospital to diarrhoeal death rates in Bangladesh and concluded that rotavirus is responsible for 5,600-9,400 child deaths in Bangladesh each year. This provides a useful figure to estimate the health benefit of an effective vaccine.
Characterizing rotavirus strains in Bangladesh
There are different strains of rotavirus. Immune protection against one strain does not guarantee protection against another. In the ICDDR,B’s Virology Laboratory, rotavirus strains identified from stools of patients participating in the hospital surveillance in Dhaka and Matlab have been monitored and characterized. Since 1992, rotavirus has been detected in stools of one-fourth of all tested patients in the two hospitals. Rotavirus has two primary antigens-the G antigen and the P antigen that affect the immune response. Genetic characterization showed that the distribution of the rotavirus genotypes changed over time (Figure). During 1992-1997, the most common rotavirus genotype was G4, accounting for 47% of the typeable rotavirus strains, but they gradually decreased and became a less common rotavirus strain over time (1.2% during 2005-2006). The distribution of G2 strains, on the other hand, remained nearly unchanged until rotavirus season 2004-2005 (19.5% during 1992-1997 and 16.2% during 2001-2005). However, in the rotavirus season 2005-2006 (43.2%), it suddenly became the most prevalent genotype. G12 strains which showed up in Bangladesh in 2000 reached 13.6% in the latest rotavirus season (2005-2006).
Analysis of the P genotype showed that the rotavirus strains with the P[8] specificity comprised 76.4% of the circulating strains during 2001-2005, and non-P[8] strains were 21.9%. The non-P[8] strains represented more than half (56.8%) of the strains during the rotavirus season
2005-2006. The currently-licensed rotavirus vaccines have shown high efficacy in trials and have focused on the role of the major G genotypes, but the role of the P genotypes has not been addressed clearly. These vaccines include the P[8] specificity, and it remains to be seen how the vaccines will perform in settings where the non~P[8] types are prevalent.
Rotavirus vaccine studies in Bangladesh
As a first step to evaluate the efficacy of the new rotavirus vaccines in Bangladesh, The ICDDR,B scientists conducted a study in urban Dhaka to evaluate the safety, the immune response, and the impact of co-administration of RotaRix vaccine at the same time as oral polio vaccine, another live virus vaccine that is active in the infant gut. Two hundred ninety-four healthy infants were randomly assigned to 4 groups to receive either: RotaRix with oral polio virus vaccine, RotaRix without oral polio vaccine, placebo with oral polio vaccine, and placebo without oral polio vaccine. The antibody response of rotavirus was assessed by measuring the seroconversion rate for antirotavirus IgA antibodies and seroprotection rates for anti-polio type 1,2,3 antibodies using a virus neutralization assay.
There were no clinical differences in tolerability between the groups. Anti-rotavirus IgA seroconversion rate in the RotaRix group where oral polio vaccine was administered concomitantly was 57% compared to 67% where RotaRix was administered alone. The serconversion rate in the pooled placebo group was 19%. No significant difference was observed in oral polio virus seroprotection rates between the groups. The ICDDR,B scientists concluded that the RotaRix vaccine was well-tolerated with a good safety and immunogenicity profile in this setting. No significant difference was noted in the immune response when two doses of the RotaRix vaccine were co-administered with oral polio vaccine compared to two RotaRix doses when oral polio vaccine was given apart.
Defining incidence of intussusception in Bangladesh in preparation for a Phase Ill Trial of a new rotavirus vaccine
An earlier rotavirus vaccine-RotaShield-was removed from the market b~cause of an increased incidence in intussusception following the administration of the vaccine. Intussusception is a severe medical problem in infancy where one portion of the bowel slides into the next, much like the pieces of a telescope. Although the new vaccines have not demonstrated any increased risk of intussusception, any evaluation of live rotavirus vaccin~ needs to include the capacity to recognize, rapidly diagnose, and appropriately treat intussusception. In 2004, scientists at ICDDR,B established an ongoing population-based surveillance for intussusception in the ICDDR,B~s Matlab field site in anticipation of conducting a large vaccine trial of a new rotavirus vaccine. In addition, the scientists reviewed data on previous hospital admissions to identify possible cases of intussusception. As part of their routine monthly visit, the community health research workers visited households of all children aged less than 2 years in the Matlab surveillance area and asked if they had experienced any symptoms consistent with intussusception. Suspected cases were referred to the Matlab hospital for evaluation. The study medical officers routinely visited all the ICDDR,B treatment centres, 4 government hospitals, and 3 district-based clinics to detect cases of intussusception. They also examined all children aged less than 2 years, admitted to the ICDDR,B Matlab Hospital and community treatment centres, with ~omplaints of diarrhoea. During July 2004-June 2006, 1,416 patients had clinical examinations. Ultrasongraphy was conducted in 120 patients who were admitted to the
Matlab Hospital or referred from the field. The community health research workers referred 40 children with suspected cases of intussusception to the Matlab Hospital for further evaluation by the medical officers for clinical examination and ultrasound. Overall, there were 2 probable cases of intussusception detected. The intussusception surveillance system has been fully established to diagnose and treat and the referral of potential cases.
Phase 3 RotaTeq vaccine trial
Late in 2006, ICDDR,B reached an agreement with PATH to conduct a phase III randomized placebo-controlled trial of the RotaTeq vaccine in th~ Matlab field site. This study will enroll up to 1,780 children who live in the Matlab surveillance area and who routinely get care for their diarrhoeal illness at the ICDDR,B’s Matlab Hospital. Data from Bangladesh will represent the primary evaluation of the effectiveness of the vaccine in low-income countries in Asia. We expect the results to inform vaccine policy for Bangladesh and for tens of millions of children in the region.
The diverse work on rotavirus in 2006 illustrates the benefits of cross-divisional collaboration. The epidemiologists in the Public Health Sciences Division oversee the population-based surveillance in Matlab and collaborate with the clinical scientists at the Matlab Hospital to identify appropriate patients for stool testing. These provide pathogen-specific population-based estimates and also provide remarkably unbiased population-based samples for detailed laboratory analysis and genotyping in the Laboratory Sciences Division. All of this provides a productive environment to support globally-important vaccine trials. The Programme on Infectious Diseases and Vaccine Sciences will continue to support productive collaborations on rotavirus and across the broad range of ICDDR,B’s work on infectious diseases.


Courtesy of The News Today

Related News

World Chocolate Day 2023: From history to celebration all you need to know

News Desk : dhakamirror.com World Chocolate Day, celebrated on July 7 each year, is a delightful occasion that brings people together. On World Chocolate Day, people indulge in a wide array of chocolate-infused delights, ranging from chocolate milk and hot chocolate to candy bars, cakes, and brownies. It is a time to revel in the ... Read more

Saudi Arabia: What happens to the 100 million Jamarat pebbles after Hajj?

World Desk : dhakamirror.com The annual Hajj pilgrimage, one of the five pillars of Islam, is a time of deep spiritual reflection for millions of Muslims. One of the most significant rituals during Hajj is the stoning at Jamarat, where pilgrims throw pebbles at three pillars, symbolising the rejection of evil. With over 1.84 million ... Read more

Still no facilities for cyclists

World Bicycle Day today Shahin Akhter Bicycles are the cheapest and most environment-friendly mode of transport in easing traffic congestion and reducing environmental pollution in the capital city, said green activists and entrepreneurs. Absence of separate lanes on roads and increased value added tax on spare parts, however, are hindering this mode of transport from ... Read more

Which are the 10 largest airports in the world?

The scenario of the global air transportation sector has drastically changed over the last few decades that has been subject to many variables over the past decade. Air travel is not only the most sought after and popular means of travel for long-distance but has made a major contribution to the world economy. It may ... Read more

Celebrating World Samosa Day

September 5 is celebrated as World Samosa Day and the day is solely dedicated to the crunchy oily snack. Be it rains or winter or summer, samosas are our savour. For those unaccustomed to the humble street food item, it’s a triangular-shaped pastry that comes with a range of fillings. Different parts of the world ... Read more

BRAC University: The World Champions

On January 3, members of 400 participating teams along with distinguished guests gathered at the Main Hall of Technische University, Berlin. Thousands if not millions watched the live feed online, from all around the world, eagerly and anxiously waiting for an announcement, the results of the World Universities Debating Championship 2013(WUDC 2013). The tournament is ... Read more

The land of beauty

by Mahfuzul Haque Bangladesh, a South-Asian country wrapped up with great streaming rivers, is indeed a land of green and natural beauty. The land possesses the longest sea beach and is home to the Royal Bengal Tiger. Sundarbans is also the biggest mangrove forest in the world. The country, once part of undivided Bengal, is ... Read more

Tourism in Bangladesh: problems and prospects

by Ziaul Haque Howlader Forty years has elapsed of Bangladesh’s tourism industry, yet we still see it in a nascent position in comparison to our neighbouring countries. Despite having all the potential to flourish, tourism in this country has been growing at a very slow pace. Bangladesh is not known as a tourist destination in ... Read more

A brief life sketch of Sir Jagadish Chandra Bose

Obaidur Rahman Born on 30th November, 1858, in the Rarikhal village of Bikrampur during the British era, which is now under the Munshiganj district of Bangladesh; Sir Bose was all together a physicist, biologist, botanist, archeologist and the author of the very first major work in the arena of Bangla science fiction, Niruddesher Kahin, written ... Read more

Focusing on community strength for disaster preparedness

OP-ED Focusing on community strength for disaster preparedness We can mobilise all the communities at every corner of Bangladesh and we will discover that they all have the same potentials. They by themselves will find a way out of their problems, writes M Mizanur Rahman. INVESTMENT in disaster preparedness can save five times as much ... Read more

Tourism prospect of Bangladesh

OP-ED Tourism prospect of Bangladesh If tourism is given due honour of industry and if both government and private organisations equally come forward for its development then it would open doors of immense possibility for us. At present, in our gross domestic product, the role of tourism is below one per cent. If it could ... Read more

New policy to promote tourism industry

The Nepali government has brought new tourism policy to promote tourism industry, The Himalayan Times reports. Addressing a press meeting, Minister for Tourism and Civial Aviation Hisila Yami said the ministry is planning a curriculum regarding tourism and the development of a separate Tourism University. “European arrivals are declining due to the global financial crisis ... Read more

A 19th-century Bengali scholar

By Monty Siddique for The News Today Abu Saleh Mohammad Siddique, whose ancestral home was in Tetulia (Zamindar family), Satkhira, Bangladesh, studied English Language and English Literature at St. Xavier’s College, Kolkata. He breathed his last in June 2007 and is buried in the Muslim section of the Greenford Cemetery in the London Borough of ... Read more

A modern day kobiraj

Jawad Hossain Nirjhor for The News Today This article is about alternative medical practices that are adopted by poor people suffering from myriad illnesses, giving us a glimpse of the health conditions and sufferings of the underprivileged population in this country. Afsar Ahamed lay near a corner of a street in Hatirpool, huddled in pain. ... Read more

The story & esoteric significance of Rath Yatra

By Dr. Subrato Ghosh for The News Today The story of the origin of Rath Yatra given by the Goswamis is practically unknown. As the gopis think and cry for Krishna, so He too was always immersed in their thought and would feel acute pangs of separation. HISTORY OF RATHA-YATRA Once Krishna was deeply thinking ... Read more

Rabindranath: The Contemporary Forever!

By Aly Zaker It was in August of 1971. I was on an official mission of the Swadhin Bangla Betar Kendra, escorting some foreign dignitaries to the refugee camp in the Salt Lake area ofCalcutta. After my official duty was over as I was getting ready to leave, I heard that the Mukti Shangrami’ Shilpi ... Read more

Struggle to Survive

By Jawad Hossain Nirjhor The ready-made garment industry employs around 3.5 million workers and accounts for 80 percent of the total export earnings is mainly depends on women workers .Following the countrywide demonstration last year, the minimum wage for the garment workers was slightly increased. On the eve of May Day, it is time to ... Read more

Junk science

Scientists are increasingly worried about the amount of debris orbiting the Earth, writes Dr K.H. Amin February 10th 2009 began like every other day in Iridium 33’s 11-year life. One of a constellation of 66 small satellites in orbit around the Earth, it spent its time whizzing through space, diligently shuttling signals to and from ... Read more

Agricultural breakthroughs

Khamin writes about the researches that have made positive differences to our agriculture sector Being mainly an agrarian economy with agriculture being the largest producing sector, the increasing performance in the sector in Bangladesh, has been fuelled by various scientific researches conducted over the past three decades. The fruition of the researches has brought about ... Read more

World’s largest mangrove forest

The Sundarbans, the largest single tidal halophytic mangrove forest in the world, is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests. The name Sundarban can be literally translated as “beautiful jungle” or “beautiful forest” in the Bengali language. The name may have been derived from the Sundari ... Read more