Whack-a-measles: Resurgence of eradicated disease points to dangers of vaccine hesitancy

High vaccination rates help Hong Kong hold back measles outbreak

Whack-a-measles: Resurgence of eradicated disease points to dangers of vaccine hesitancy
Whack-a-measles: Resurgence of eradicated disease points to dangers of vaccine hesitancy
  • Measles was thought eliminated but outbreaks since 2018 have led to a resurgence.
  • A vaccine has been in use since the 1960s but vaccine hesitancy and antivaxxer movements have weakened the nets of protection and herd immunity in places as disparate as the U.S., the Philippines or the Democratic Republic of Congo.
  • An outbreak in Hong Kong was quickly contained thanks to widespread vaccination and an effective healthcare system.

HONG KONG. For a disease that should have been a bad memory by now, measles is making a comeback. Vaccine hesitancy and antivaxxer attitudes are some of the key reasons behind the resurgence of this virulent disease around the world.

The number of U.S. measles cases recorded by the Centers for Disease Control and Prevention (CDC) in 2019 was 1,282, nearly quadruple the 375 cases reported in 2018. One outbreak in the northwestern city of Seattle led to schools being cancelled for at least 800 kids.

There were a number of outbreaks across Latin America and Africa, with the Democratic Republic of the Congo (DRC) recording a catastrophic quarter of a million infections. Immunization campaigns in the DRC have been hampered since 2018 because of poor infrastructure and social unrest.

There have also been big outbreaks across Asia and the Pacific last year, according to the World Health Organization (WHO)

In the Pacific, the island of Samoa had a massive outbreak that infected over 3% of the population and killed 83 people. There were almost 100 cases in the first four months of last year in Australia. New Zealand reported 72.

Mainland China reported almost 4,000 cases in 2018 and almost 600 cases in the first quarter of 2019. The WHO certified in 2015 that Japan had eliminated measles but the country reported almost 400 cases in the first four months of 2019. 

The Philippines had the largest outbreak in Southeast Asia in 2019 with more than 42,000 cases. In the Philippines, vaccination coverage is just 67%.

Hong Kong eliminated measles in 2016 but, last year, it emerged as a case study of the importance of maintaining constant vigilance and a strong immunization net. 

Hong Kong, which has a strong vaccination program and strong healthcare system, had 91 cases last year, a six-fold increase compared to the previous year. Twenty-nine out of the 91 cases were related to an outbreak at the Hong Kong International Airport in March but it was quickly curbed within two months, which is a very different outcome compared to other hot zones. 

Still, the strong vaccination program in Hong Kong may have been instrumental in keeping the outbreak from spreading. 

“Aside from the swift response from the Department of Health, Hong Kong’s high vaccination rate for the measle virus is a definite contributing factor,” Dr. Lee Ching Kong Victor, head of the 24-hour out-patient center at Hong Kong Baptist Hospital, told Anticentric. 

“In Hong Kong, over 95% of residents are vaccinated due to our vaccination program, which covers all infants. This has given Hong Kong strong protection against the virus with new cases mostly being imported.” 

The biggest outbreaks have happened in places with much lower vaccination coverage. 

Measles or rubeola is caused by a highly contagious RNA virus. Symptoms include high fevers, runny nose, inflamed eye as well as small white spots that form inside the mouth and a red flat rash that starts in the face and moves to the rest of the body. 

The WHO says measles is particularly contagious because it can be transmitted via droplets from the nose, mouth or throat of infected persons along with a long gestation period. Initial symptoms may only appear 10 to 12 days after infection. 

The WHO’s Global Vaccine Action Plan, which aims to eliminate measles in five WHO Regions by this year, is still active. Given the outbreaks over the past couple of years, it is unlikely to meet this target. The major obstacles ahead have to do with poor healthcare infrastructure and, increasingly, the rise of vaccine hesitancy or anti-vaxxers

The WHO actually included vaccine hesitancy, the reluctance or refusal to use vaccines, as one of the top 10 threats to global health in 2019. According to the organization, vaccine hesitancy could threaten or even reverse the progress made in tackling vaccine-preventable diseases like measles.

The leading cause of vaccine hesitancy appears to be complacency caused by the perception that diseases like measles have been generally brought under control and fear of any possible side effects of vaccines or other long-term complications, including cancer. 

None of these claims have been backed by scientific data. In fact, links between vaccines and autism have been discredited. Most of these claims were based in outlined in a discredited 1998 paper penned by Andrew Wakefield, who later lost his license to practice medicine. (Read more in Vaccines: Level of mistrust remains high despite overabundance of data.)

“There have been no legitimate studies which have shown that measles vaccines pose major health risks to patients,” said Lee. “The vaccine has proven to be safe and effective by the WHO and has saved countless lives worldwide.”

There are decades of data to back the use of the measles vaccine, which has been in use since the 1960s. The WHO recommends the use of the vaccine for all susceptible children and adults for whom contraindications are not an issue. 

Between 2000 and 2018, the use of the measles vaccine helped reduce the number of measles deaths around the world by 73%.