Eye on ID

‘Anti-vaxxers’: A menace to public health

Vaccines have been a wonderful addition to the medical armamentarium and have made major inroads in reducing morbidity and mortality due to infectious diseases. They have been the mainstay of effective public health prevention activities. That said, no vaccine is perfect, both in terms of vaccine efficacy and safety; no vaccine has demonstrated 100% efficacy, and there are certainly negative effects experienced by some vaccine recipients with all vaccines. The latter observation — negative effects — has led to a movement of parents refusing to vaccinate their children based on perceived risks of the vaccines along with a lack of sufficient perceived benefit. This movement is particularly strong in certain communities in the Western United States.

Marjorie P. Pollack

From the public health perspective (and that of the clinical infectious disease world and pediatric practices), the anti-vaccination movement (aka “the anti-vaxxers” or, to be more politically correct, “vaccine hesitators”) is a key deterrent to the control and elimination of vaccine-preventable diseases. In fact, the movement has been responsible for unacceptable morbidity and mortality worldwide.

In the developing world, polio eradication efforts have been hampered through misinformation campaigns. In the three remaining polio-endemic countries (Nigeria, Pakistan and Afghanistan), there have been claims that the vaccination programs have been a cover for Western powers to sterilize the population or spread HIV.

In the developed world, the anti-vaccine movement has been more insidious, spreading erroneous claims of higher risks for severe adverse events associated with the vaccines, leading to years of costly scientific studies to debunk those myths. To complicate matters, through the years there have been physicians who have played into the hands of these movements, at times for financial gain. Avoidance of measles immunization has been a particular focus of the anti-vaxxers. A glaring example of misinformation is the story behind Andrew Wakefield’s claims of a new syndrome associated with the measles, mumps and rubella (MMR) vaccine — autism and gastrointestinal disease — published in The Lancet in 1998. Other physicians, swayed by the misinformation, helped perpetuate the problem through falsifying vaccination records, permitting nonvaccinated individuals to attend schools and serve as reservoirs for outbreaks of vaccine-preventable diseases. The resultant decrease in vaccination levels against measles led to increases in measles incidence first seen in the United Kingdom, followed by the U.S.

During the period 2001-2013, there was a major increase in the number of reported cases of measles in the U.K., including three deaths (note that the Wakefield paper was published in 1998). The reported number of cases decreased in 2014 and 2015 (Wakefield was thoroughly discredited and lost his medical license in the U.K. in 2010). However, cases increased significantly in 2016 (488 measles cases reported from January to September 2016 — a more than fivefold increase in reported cases compared with 2015, with most cases seen in unvaccinated individuals. Many cases were associated with attendance at music festivals and other public events. Despite the discreditation of Wakefield’s work and the retraction of his original paper, the autism theory lives on in the anti-vaxxer community in the U.K. and U.S.

In 2015, there was a major outbreak of measles in the U.S. linked to exposure at an amusement park in California, leading to cases in multiple states, most likely associated with a park visitor who was infected overseas and visited the park during the infectious period. The outbreak included 188 cases from 24 states and Washington, D.C., with many of the cases unvaccinated or inadequately vaccinated. Viral studies identified a measles virus from the B3 clade that was identical to the virus associated with a major outbreak in the Philippines in 2014.

In September 2016, the Pan American Health Organization and WHO declared the Americas free of measles. Measles is the fifth vaccine-preventable disease eliminated in the Americas, following smallpox in 1971, polio in 1994, and rubella and congenital rubella syndrome in 2015. Why should this influence the anti-vaxxers? The declaration that local transmission of measles had been eliminated was not affected by the pockets of susceptible people (luck and not science), and with the elimination of local transmission, why should they subject their children to vaccines with potential side effects when the threat of disease is low? That is, in their thinking, the risk of acquiring the disease is less than the risk of a side effect from the vaccine.

Donald Kaye

What is not understood by some people is that while local transmission of the disease has been eliminated, outbreaks still occur — caused by importations of the virus, with secondary and tertiary cases resulting from exposure to these imported cases. These exposures often occur at mass gatherings, such as a visit to an amusement park, and are not due to residual local transmission; it is all in the semantics.

What is also not understood by the anti-vaxxers are the dangers of the disease itself. Disease tends to be more severe in children aged younger than 5 years and adults aged older than 20 years. The immediate dangers include diarrhea (with subsequent dehydration) in 8% of cases, otitis media in 7% of cases, pneumonia (primary viral or secondary bacterial) in 6% of cases, and acute encephalitis in one of every 1,000 cases (with a case fatality rate of approximately 15%). A sobering statistic is that as many as 30% of reported cases have one or more complications of the disease, and one to two per 1,000 patients with measles die from complications.

Perhaps more widespread information dissemination on the dangers of the long-term sequelae of measles infection — specifically, subacute sclerosing panencephalitis (SSPE) — would have an effect. During IDWeek 2016, Kristen Wendorf, MD, MS, from the Immunization Branch of the California Department of Public Health (CDPH), and colleagues presented data on the incidence of SSPE in the state. According to their data, among measles cases reported to the CDPH during 1988-1991, the incidence of SSPE was 1:1367 for those aged younger than 5 years and 1:609 for those aged younger than 12 months. Prior to this, the estimated incidence rate ranged from a high of 1:3,584 to a low of 1:25,000. SSPE has a latent period of years (usually 7-10 years) before onset of the irreversible, progressive and lethal disease. Therefore, any woman with a child who had measles is dealing with a potential ticking time bomb.

One public health issue is that if the vaccination rate should fall below 90%, there is the danger of a loss of herd immunity and the occurrence of measles epidemics. Another public health danger is that of exposure to measles of an immunocompromised individual or a child too young to be immunized. Measles is particularly deadly in this population. It is not hard to imagine a child of an anti-vaxxer being exposed to measles abroad or from a foreign visitor and then exposing a child too young to be immunized or an immunocompromised child next door. While some of those who are unvaccinated have true religious reasons for avoiding vaccination, they are in a minority and often clustered without major contact with outsiders. The anti-vaxxer community is more of a danger.

Another recent event that has fed into the anti-vaxxers’ armamentaria was a low-efficacy vaccine leading to many vaccine failures (defined as adequately vaccinated individuals who develop the disease). The 2014-2015 influenza vaccine was a mismatch whereby 58% of the circulating influenza A(H3N2) viruses were not the virus contained in the vaccine. Estimates of vaccine efficacy against the H3N2 virus during the 2014-2015 influenza season ranged from 10% to 12%. Events such as these feed into the anti-vaxxer thinking that they should not expose themselves (or their loved ones) to the potential dangers of a vaccine when it is not even efficacious in preventing the disease.

In conclusion, let us not underestimate or ignore the dangers of the anti-vaxxers. They can cause a great deal of damage. And let us hope that the new administration does not heed the siren calls of the anti-vaxxers.

Editor’s note: Pollack was accused of participating in a government cover-up on vaccine complications in the book, “DPT: A Shot in the Dark,” by Harris Coulter and Barbara Loe Fisher (1985).

Disclosures: Kaye and Pollack report no relevant financial disclosures.

Vaccines have been a wonderful addition to the medical armamentarium and have made major inroads in reducing morbidity and mortality due to infectious diseases. They have been the mainstay of effective public health prevention activities. That said, no vaccine is perfect, both in terms of vaccine efficacy and safety; no vaccine has demonstrated 100% efficacy, and there are certainly negative effects experienced by some vaccine recipients with all vaccines. The latter observation — negative effects — has led to a movement of parents refusing to vaccinate their children based on perceived risks of the vaccines along with a lack of sufficient perceived benefit. This movement is particularly strong in certain communities in the Western United States.

Marjorie P. Pollack

From the public health perspective (and that of the clinical infectious disease world and pediatric practices), the anti-vaccination movement (aka “the anti-vaxxers” or, to be more politically correct, “vaccine hesitators”) is a key deterrent to the control and elimination of vaccine-preventable diseases. In fact, the movement has been responsible for unacceptable morbidity and mortality worldwide.

In the developing world, polio eradication efforts have been hampered through misinformation campaigns. In the three remaining polio-endemic countries (Nigeria, Pakistan and Afghanistan), there have been claims that the vaccination programs have been a cover for Western powers to sterilize the population or spread HIV.

In the developed world, the anti-vaccine movement has been more insidious, spreading erroneous claims of higher risks for severe adverse events associated with the vaccines, leading to years of costly scientific studies to debunk those myths. To complicate matters, through the years there have been physicians who have played into the hands of these movements, at times for financial gain. Avoidance of measles immunization has been a particular focus of the anti-vaxxers. A glaring example of misinformation is the story behind Andrew Wakefield’s claims of a new syndrome associated with the measles, mumps and rubella (MMR) vaccine — autism and gastrointestinal disease — published in The Lancet in 1998. Other physicians, swayed by the misinformation, helped perpetuate the problem through falsifying vaccination records, permitting nonvaccinated individuals to attend schools and serve as reservoirs for outbreaks of vaccine-preventable diseases. The resultant decrease in vaccination levels against measles led to increases in measles incidence first seen in the United Kingdom, followed by the U.S.

During the period 2001-2013, there was a major increase in the number of reported cases of measles in the U.K., including three deaths (note that the Wakefield paper was published in 1998). The reported number of cases decreased in 2014 and 2015 (Wakefield was thoroughly discredited and lost his medical license in the U.K. in 2010). However, cases increased significantly in 2016 (488 measles cases reported from January to September 2016 — a more than fivefold increase in reported cases compared with 2015, with most cases seen in unvaccinated individuals. Many cases were associated with attendance at music festivals and other public events. Despite the discreditation of Wakefield’s work and the retraction of his original paper, the autism theory lives on in the anti-vaxxer community in the U.K. and U.S.

In 2015, there was a major outbreak of measles in the U.S. linked to exposure at an amusement park in California, leading to cases in multiple states, most likely associated with a park visitor who was infected overseas and visited the park during the infectious period. The outbreak included 188 cases from 24 states and Washington, D.C., with many of the cases unvaccinated or inadequately vaccinated. Viral studies identified a measles virus from the B3 clade that was identical to the virus associated with a major outbreak in the Philippines in 2014.

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In September 2016, the Pan American Health Organization and WHO declared the Americas free of measles. Measles is the fifth vaccine-preventable disease eliminated in the Americas, following smallpox in 1971, polio in 1994, and rubella and congenital rubella syndrome in 2015. Why should this influence the anti-vaxxers? The declaration that local transmission of measles had been eliminated was not affected by the pockets of susceptible people (luck and not science), and with the elimination of local transmission, why should they subject their children to vaccines with potential side effects when the threat of disease is low? That is, in their thinking, the risk of acquiring the disease is less than the risk of a side effect from the vaccine.

Donald Kaye

What is not understood by some people is that while local transmission of the disease has been eliminated, outbreaks still occur — caused by importations of the virus, with secondary and tertiary cases resulting from exposure to these imported cases. These exposures often occur at mass gatherings, such as a visit to an amusement park, and are not due to residual local transmission; it is all in the semantics.

What is also not understood by the anti-vaxxers are the dangers of the disease itself. Disease tends to be more severe in children aged younger than 5 years and adults aged older than 20 years. The immediate dangers include diarrhea (with subsequent dehydration) in 8% of cases, otitis media in 7% of cases, pneumonia (primary viral or secondary bacterial) in 6% of cases, and acute encephalitis in one of every 1,000 cases (with a case fatality rate of approximately 15%). A sobering statistic is that as many as 30% of reported cases have one or more complications of the disease, and one to two per 1,000 patients with measles die from complications.

Perhaps more widespread information dissemination on the dangers of the long-term sequelae of measles infection — specifically, subacute sclerosing panencephalitis (SSPE) — would have an effect. During IDWeek 2016, Kristen Wendorf, MD, MS, from the Immunization Branch of the California Department of Public Health (CDPH), and colleagues presented data on the incidence of SSPE in the state. According to their data, among measles cases reported to the CDPH during 1988-1991, the incidence of SSPE was 1:1367 for those aged younger than 5 years and 1:609 for those aged younger than 12 months. Prior to this, the estimated incidence rate ranged from a high of 1:3,584 to a low of 1:25,000. SSPE has a latent period of years (usually 7-10 years) before onset of the irreversible, progressive and lethal disease. Therefore, any woman with a child who had measles is dealing with a potential ticking time bomb.

One public health issue is that if the vaccination rate should fall below 90%, there is the danger of a loss of herd immunity and the occurrence of measles epidemics. Another public health danger is that of exposure to measles of an immunocompromised individual or a child too young to be immunized. Measles is particularly deadly in this population. It is not hard to imagine a child of an anti-vaxxer being exposed to measles abroad or from a foreign visitor and then exposing a child too young to be immunized or an immunocompromised child next door. While some of those who are unvaccinated have true religious reasons for avoiding vaccination, they are in a minority and often clustered without major contact with outsiders. The anti-vaxxer community is more of a danger.

Another recent event that has fed into the anti-vaxxers’ armamentaria was a low-efficacy vaccine leading to many vaccine failures (defined as adequately vaccinated individuals who develop the disease). The 2014-2015 influenza vaccine was a mismatch whereby 58% of the circulating influenza A(H3N2) viruses were not the virus contained in the vaccine. Estimates of vaccine efficacy against the H3N2 virus during the 2014-2015 influenza season ranged from 10% to 12%. Events such as these feed into the anti-vaxxer thinking that they should not expose themselves (or their loved ones) to the potential dangers of a vaccine when it is not even efficacious in preventing the disease.

PAGE BREAK

In conclusion, let us not underestimate or ignore the dangers of the anti-vaxxers. They can cause a great deal of damage. And let us hope that the new administration does not heed the siren calls of the anti-vaxxers.

Editor’s note: Pollack was accused of participating in a government cover-up on vaccine complications in the book, “DPT: A Shot in the Dark,” by Harris Coulter and Barbara Loe Fisher (1985).

Disclosures: Kaye and Pollack report no relevant financial disclosures.