Esper Kallás, who heads Latin America’s leading producer of vaccines, delivered the Second 2023 FAPESP Lecture on “Viruses, pandemics and vaccines”. He spoke about the “100 Day Mission” to produce novel vaccines in just over three months (photo: Renato Rodrigues/Butantan Institute)
Published on 06/05/2023
By José Tadeu Arantes | Agência FAPESP – The world is highly likely to face new pandemics in the short or medium term, and we must be prepared, warned infectious disease specialist Esper Kallás in the Second 2023 FAPESP Lecture, delivered on May 25 on the subject of “Viruses, pandemics and vaccines”.
Kallás heads Butantan Institute, a biomedical research center linked to the São Paulo State Government’s Department of Health and the leading producer of immunotherapeutic serums and vaccines in Latin America.
Being prepared means combating the “disinformation pandemic” manufactured by science deniers, and quickly and efficiently establishing initiatives such as the so-called “100 Day Mission” to reduce from 300 to 100 days the time taken to detect the infectious agent, create a safe and effective treatment and develop a vaccine. Kallás explained the progress Butantan Institute has made so far toward achieving the goal.
“The first step, which is crucial for any country, entails having a surveillance system capable of detecting any anomaly. To this end, it must define clinical syndromes, detect and track pathogens, research novel agents, and establish epidemiological trends,” he said.
Butantan Institute has such a system, he added: the Center for Viral Surveillance and Serological Assessment (CeVIVAS), which is equipped to conduct molecular diagnosis and genomic classification regarding SARS-CoV-2, influenza and dengue.
The second step, he continued, is to create a form of treatment. The fastest way to do this, in addition to tracking commercially available products, is via monoclonal antibodies or pools of antibodies that act against infections. Butantan Institute has two such units. One dates from the establishment of the institute and produces hyperimmune serums obtained from the plasma of vaccinated animals. The other, substantially developed during the COVID-19 pandemic, identifies and produces neutralizing monoclonal antibodies.
The third step is vaccine production. “Brazil’s role in the development of vaccines against COVID-19 is unquestionable. The four vaccines used in Brazil were all produced only here or here as well as elsewhere. Together with scientists in just a few other countries in the world, Brazilian researchers contributed most to the effort to make these vaccines part of our day-to-day lives. We’ve experienced this intensely in the last few years,” he said.
Kallás cited the different platforms available for production of vaccines, briefly describing their pros and cons, from messenger RNA and DNA to inactivated or attenuated whole agent vaccines, viral vector vaccines, protein subunit vaccines, carrier proteins in conjugate vaccines, and vaccines produced in eggs. The main target at this time is flu, because this is the main pandemic threat on the horizon, he warned.
Risk factors
Several general factors contribute to the risk of new pandemics, according to Kallás: world population growth, increasing mobility, rising numbers of people who live on the frontier between civilization and wildlife, more people with comorbidities and primary immunodeficiencies, more frequent disasters caused by human activities, and, last but certainly most important, climate change.
“The world population surpassed 8 billion in 2022 and is expected to peak at 10.4 billion by 2080, after which the growth curve will turn down. This alone increases the number of people who may be susceptible to an infectious agent. With the increase in mobility due to air travel, it’s possible to reach anywhere in the world in less than 24 hours. That’s a major advantage for a transmissible agent because it can be present in different places within a very short time span,” Kallás said.
Humans increasingly encroach on wildlife habitats because of this demographic pressure and the ease of travel. Direct contact with the animals that live in these areas, by eating them or interacting with their droppings, for example, puts humans at the mercy of pathogenic agents against which we have not developed defenses. “Bats alone carry more than 40,000 viruses that can infect mammals,” he said.
On the other hand, the number of people with comorbidities or primary immunodeficiencies is steadily increasing as a proportion of the total population owing to rising longevity and the higher probability of surviving disease, both of which are major achievements of science and medicine. “These groups are more likely to be infected, host mutations of infectious agents, and transmit them to other people. In the case of COVID-19, some variants may have emerged because the virus continued to multiply for long period in immunodeficient patients who were unable to get rid of it completely,” Kallás said.
All these factors comprise a scenario favorable to the emergence of new pandemics. The possibilities are even more alarming in light of the disasters caused by human activities, such as the Mariana and Brumadinho mining sludge dam collapses (in 2015 and 2019 respectively), both of which had a huge social and environmental impact, let alone the climate crisis.
“Extreme weather events have varying impacts on human health. Extremely warm weather can cause health problems, but climate change can also facilitate the spread of diseases transmitted by respiration, water or food, as well as dissemination of vectors in regions where they wouldn’t normally be. An example is the current outbreak of dengue fever in Santa Catarina [a state in Brazil’s South region],” Kallás said, recalling that Aedes aegypti, the mosquito that transmits dengue, was not found in the South previously owing to the region’s relatively cool climate.
In this context of general factors favorable to a possible new pandemic, the World Health Organization (WHO) has issued the following list of priority pathogens — agents that can cause outbreaks or pandemics — to guide global investment, research and development, especially in vaccines, tests and treatments: COVID-19; Crimean-Cong hemorrhagic fever; Ebola virus disease and Marburg virus disease; Lassa fever; Middle East respiratory syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS); Nipah and other Henipavirus diseases; Rift Valley fever; Zika; and “Disease X”. According to the WHO, “Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease.”
Kallás is a professor in the Department of Infectious and Parasitic Diseases at the University of São Paulo’s Medical School (FM-USP). He is a former head of clinical research at FM-USP’s general and teaching hospital (Hospital das Clínicas). During the COVID-19 pandemic, he was a front-line physician, a member of the São Paulo State Contingency Center, and principal investigator for the Phase 3 clinical trials of the CoronaVac vaccine.
In the Q&A session after the lecture, Kallás recalled that the containment measures implemented during the pandemic in São Paulo state prevented a collapse of health services such as the one seen in New York city in the United States.
The Second 2023 FAPESP Lecture on “Viruses, pandemics and vaccines” was attended by Professor Marco Antonio Zago, President of FAPESP; Professor Marcio de Castro Silva Filho and Professor Carlos Américo Pacheco, Scientific Director and CEO of FAPESP respectively; Andrew Simpson, who led the FAPESP Genome Project; and Walter Colli, a former head of Butantan Institute.
For Zago, construction of a biosafety level 4 laboratory for research on highly dangerous microorganisms should be studied. “It’s not a project for FAPESP, but it could be a project for São Paulo state. The state could decide to invest in a BSL-4 lab," he said.
The Second 2023 FAPESP Lecture on “Viruses, pandemics and vaccines” can be watched at: www.youtube.com/watch?v=4i2k9WuaGMY.
Source: https://agencia.fapesp.br/41582
