UPDATE: Merck says switching cell lines would impact safety and quality

Anti-abortion group won't judge parents who choose Merck & Co's MMR vaccine

By Gareth Macdonald

- Last updated on GMT

Related tags Vaccination

Measles: a moral choice
Measles: a moral choice
The anti-abortion group that blames Merck & Co for the recent US measles outbreak says it would not judge parents who have children vaccinated with MMR II for the good of society.

The group – Children of God for Life – issued a press release last Thursday arguing that, rather than being the fault of parents who did not vaccinate their children, the measles outbreak at Disneyland last month ​was a result of Merck & Co’s decision to stop providing separate measles and mumps vaccines in 2009.

Since then​ the only measles vaccines available in the US have been in Merck’s MMR II or ProQuad products, which is a problem for the anti-abortion group because the rubella component in the two products is produced using the WI-38 cell line.

WI-38 cells are lung cells from a foetus aborted at a Swedish hospital in 1962​. Researchers at the Wistar Institute for Anatomy and Biology in the US found they could use them to grow viruses, including weakened strains of rubella used in vaccines.

Children of God for Life director Debi Vinnedge told Biopharma-Reporter.com “There are numerous moral cell lines that could be used in the US as well. There is no reason to use WI-38​,” citing a rubella vaccine made using rabbit cells by Japan’s Kitasato Institute as an example.

Merck responds

Merck vaccines spokeswoman Deb Wambold confirmed the firm uses WI-38 and explained that switching to another cell line would be a considerable challenge and impact both product safety and product quality. 

Because the process to develop a vaccine is specific for the cell line that the vaccine is derived and produced in, it is not possible to simply substitute one cell line for another to prepare a vaccine.​"

She added that: “In light of the extensive scientific and regulatory requirements for developing alternate vaccines, it would be exceedingly difficult to develop alternative vaccines prepared in a different manner. Even then, there can be no guarantee that alternate vaccines with the degree of safety and efficacy comparable to currently licensed vaccines could be developed​.” 

This view was ecohed by world renowned virologist John Oxford from Blizard Institute, Queen Mary College, London, who told us "It would be very costly to change all this now and moreover the line has proven to be safe​."

He went on to say "The Swedish lady from whose baby the line was derived gives her blessing for its use and seemed pleased to me that something like this came of the abortion" ​adding that "to my knowledge most faiths have backs this and I do not really see how the blame for not vaccinating children can be placed on anyone other than the parents​."

Japanese rubella epidemic

How viable an option the Kitasato Institute product would be for US citizens is also debatable as the vaccine is not approved by the US FDA and is in short supply as a result of Japan's efforts to address its rubella epidemic​.

According to Japan’s National Institute of Infectious disease (NIID)​ the country saw 15,000 cases of rubella and 43 cases congenital between October 15, 2012 and March 2, 2014.

The NIID attributes the outbreak to changes in national vaccination programmes​ and a failed MMR vaccine launched in 1989 and withdrawn in 1993​ after cases of aseptic meningitis linked to the mumps component that meant some children were not vaccinated.

This fits with the age distribution seen in the 2013 rubella outbreak​ ,which mostly affected men aged 35 to 51 who were children when only girls were routinely vaccinated and men and women aged 24–34 years who were young when coverage rates fell in 1994.

Herd immunity

Disease outbreaks like the one in Disneyland occur when an infectious agent passes from an infected person to a susceptible individual. Immunization seeks to prevent this on the basis that immunized people are less likely to transfer a virus or bacteria between two susceptible people.

Once enough members of a population are immune – either as a result of vaccination or because they have survived infection – the infectious agent cannot spread significantly, even among unvaccinated people, and “herd immunity” has been achieved.

For measles the herd immunity threshold is between 90 and 95% according to the World Health Organisation (WHO), meaning that a majority of US citizens would need to be immune to measles to prevent resurgence of the disease.

Given this we asked Vinnedge if her group would consider putting its objections on hold and backing either of the two measles vaccines approved in the US for the good of society.

She told us: “I would never advocate one way or another to either use or refuse any vaccine, mainly because I believe it to be a parental and medical decision based on the individual child.​ 

And as there are moral reasons, I would not judge one person's conscience from a religious standpoint​” she added. 

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