The drive to effectively vaccinate the world’s population against COVID-19 has seen many other important vaccines lose their place in the public spotlight. However, one particular group of vaccines was back in the news in April after the Chinese Academy of Medical Sciences (CAMS) named their development as one of China’s most important medical science achievements of the 21st Century.
The vaccines, the first of its kind worldwide, protect against enterovirus 71 (EV71), a dangerous virus that can cause hand, foot and mouth disease (HFMD), a highly contagious illness that affects children.
The vaccine development project was carried out by several research institutions including the Institute of Medical Biology (IMB), an organization under the CAMS, and the National Institutes for Food and Drug Control, as well as pharmaceutical companies such as China National Biotech Group (CNBG) and SINOVAC Biotech Co. Ltd., according to the CAMS.
The vaccine developed by the IMB was approved by the China Food and Drug Administration on December 3, 2015, followed by two others, approved respectively weeks later and approximately a year later, Li Qihan, Director of the IMB and one of the developers of the vaccine, told Beijing Review.
In 2016, doctors began to administer the vaccines nationwide. With about 10 million doses delivered annually onward, according to the CAMS, the vaccination program has so far reduced the death toll from HFMD by more than 90 percent in the country.
“Vaccination is the most effective method to prevent and control the disease. It can give children immunity to shield them from the virus,” said Li.
At the time the IMB vaccine was approved, Bernhard Schwartländer, representative of the World Health Organization (WHO) in China, praised it as a crucial tool for controlling the illness. “There is no specific treatment for the EV71 disease, which is what makes the development and licensing of this vaccine so important,” Schwartländer said.
A highly infectious disease
The HFMD is a communicable disease with high incidence rate in China. The transmission coefficient of HFMD can be as high as 4.2-6.5, which is three times that of COVID-19, Zeng Guang, chief epidemiologist of the China Center for Disease Control and Prevention (China CDC), told the press in June 2020.
In March 2008, during an outbreak in Fuyang, Anhui Province, 3,321 cases were confirmed in a roughly one month, resulting in 22 deaths.
After that, the national health authority listed HFMD as a category C infectious disease, joining 12 other diseases including measles, mumps and influenza. According to China CDC, the nation now has 40 infectious diseases listed under the categories A, B and C, with A being the most serious and C being the least. They are classified according to factors such as incidence and harm, as well as mode and speed of transmission. Each category is managed differently, with mandatory quarantine required for category A diseases, which include plague and cholera.
Incidences of category C infectious diseases are mandatorily reported and monitored. Statistics from China CDC show that from 2008 to 2015, 13.8 million cases of HFMD were reported throughout the country, including more than 130,000 serious cases, leading to approximately 3,300 deaths. In 2018, 2.376 million cases were reported, more than any other mandatorily reported infectious disease, Zeng said.
Most cases of HFMD occur in spring and among children under 10, especially pre-schoolers. Typical symptoms are fever, poor appetite and sore throat, followed by the development of sores in the mouth and a rash on the hands and feet. However, according to the WHO, some cases of EV71 infection may progress into meningitis or encephalitis, two very serious neurological conditions that are potentially fatal.
HFMD is spread through coughs, sneezes, feces and the fluid from the blisters caused by the virus, according to medical experts. Prevention is important. Liu Qian, a mother of two in Beijing, still remembers springtime being overshadowed by HFMD epidemics. Her daughter attended a private kindergarten from 2012 to 2015. Beginning with the arrival of spring each year, it was on high alert. The teachers reminded children to wash their hands frequently and they warned parents not to take their children to crowded places. A retired doctor was hired to check children’s hands and mouths each morning. If infections were found, the classes affected or even the entire kindergarten would be closed for a period.
Now Liu’s son is in kindergarten. “The kindergarten still checks children’s hands and mouths every morning. If any symptom of HFMD is found, the sick child is not allowed entry,” she told Beijing Review. But transmission can happen before symptoms become apparent. Liu remembers that three years ago, her son’s class was closed for a week after a case was diagnosed.
Chinese researchers began working on HFMD vaccines after the outbreak in Anhui in 2008.
The disease can be caused by more than 20 kinds of enteroviruses, with coxsackievirus A16 and EV71 being the most common of these pathogens. EV71, in particular, caused 74 percent of severe cases and 93 percent of fatal cases. It is for this reason that CAMS scientists chose it first as the target for a vaccine.
Several institutions carried out the research and development respectively, and the vaccine developed by Li’s team was the first to get official approval. “The process was a joint effort that comprises steps including basic research, analysis of pathogens’ biological characteristics and how they cause infection, development of animal models and assessment of vaccine quality,” Li told People.com.cn during an interview.
The team Li led successfully isolated and cultivated the EV71 strain, developed a testing method for the virus antigen and established a rhesus monkey EV71 infection model, which is essential for ensuring the safety and efficacy of the vaccine.
It took the researchers approximately eight years to succeed. Phase III clinical trials showed the vaccine to be 97 percent effective at preventing EV71 infection, and 100 percent effective against serious cases and death caused by the virus, Li told Beijing Review.
Upon the vaccine’s release in 2015, Schwartländer was quoted in a WHO news release as saying that “China’s scientists can be very proud of having produced the world’s first vaccine to protect against the EV71 disease. It shows the increasingly important role China is playing in global health through innovation in vaccine development and production.”
The IMB vaccine is an inactivated one. Two doses, administered one month apart, are needed for full protection. Children can receive the first dose from the age of six months.
On April 25, a woman surnamed Chen took her child to be immunized against EV71 at a community health center in Qingxiu District, Nanning in Guangxi Zhuang Autonomous Region. “I saw in the news that now is the high-incidence season for HFMD, so I think I must have my baby inoculated as soon as possible,” she told Guangxi Daily.
April 25 is China Prophylactic Vaccination Day, which was set in 1986 to promote the vaccination of children.
Jiang Lina, an expert with the Guangxi Regional Center for Disease Prevention and Control (Guangxi CDC), said, “Since EV71 vaccination started in 2016, the number of jabs given in Guangxi has been increasing year by year.”
Zhong Ge, Deputy Director the Guangxi CDC, said as of April 21, 33,659 cases of HFMD had been diagnosed in the region so far this year, higher than in the same period of 2019 and 2020. There were 36 severe cases and no lethal cases, respectively, lower than an average of more than 50 and 2 during the same period over the last five years.
However, Jiang pointed out that the overall vaccination rate in Guangxi is still not high and she called for efforts to raise public awareness of the program.
Meanwhile, Li said medical scientists are studying other HFMD pathogens, so as to develop combined vaccines to provide full-spectrum protection.
(Print Edition Title: An Injection of Hope)
Copyedited by G.P. Wilson
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