Puerto Rico Remains America's Zika Virus Leader

As of April 3, 2019, the US Centers for Disease Control and Prevention (CDC) had not reported any Zika virus cases in the USA or its Territories during 2019. 

But, the CDC did update its provisional data for 2018, reporting 72 Zika cases in the USA, and 148 cases in the US Territories, as of March 6, 2019. 

With Puerto Rico reporting 147 of the 148 Zika symptomatic cases during 2018. 

This data is actually good news when compared with 2017 when Puerto Rico reported 620 symptomatic Zika cases to the CDC. 

This information is one of the reasons the Canadian and United Kingdom health agencies have maintained their Zika travel warnings for Puerto Rico. 

The Public Health Agency of Canada reaffirmed a Level 2 Alert for travelers to Puerto Rico on January 17, 2019, recommending that Canadians ‘Practice Special Precautions’ while traveling in Zika affected destinations, such as Puerto Rico. 

Moreover, Canada said ‘pregnant women and those considering becoming pregnant should avoid travel to Puerto Rico.’   

And the UK says ‘There is a risk of Zika in this country, and pregnant women are advised to avoid travel to this country until after the pregnancy.’ 

Which presents a question, why did the CDC downgrade its Zika warnings for visitors to Puerto Rico on April 5, 2019?   

During the November 2015 – April 2016 time frame, the CDC reported 11 percent of 6,157 specimens from Puerto Rico had laboratory evidence of current or recent Zika virus infection. 

Additionally, the CDC’s action appears inconsistent with the state of Florida, which has reported 13 travel-related Zika cases during 2019. 

Since Puerto Rico is only a 3-hour flight from Florida, and approximately 1 million Puerto Ricans live in Florida, the CDC’s change to previous Travel Alerts could be considered premature, without a Zika vaccine available. 

The National Institute of Allergy and Infectious Diseases reported in August 2018 that several types of vaccines are in development, including vaccine candidates based on DNA, inactivated Zika, and live Zika. Most are in the clinical testing phase, and the medical community hopes they will be available sooner than later.   

One Zika vaccine candidate appears to be making significant progress. 

TAK-426 (PIZV) is a purified, inactivated, alum-adjuvanted, whole Zika virus vaccine candidate, which was granted FDA Fast Track designation in January 2018. 

The TAK-426 phase 1 multi-center clinical trial with 240 individuals in the USA and Puerto Rico, was last updated on March 26, 2019.   

But, since this clinical study is scheduled to be concluded in 2020, international travelers should remain patient, and follow the CDC’s Zika prevention suggestions. 

Such measures can also help minimize risk for fetal Zika virus infection.

Clinicians who suspect Zika virus disease in patients who reside in or have recently returned from areas with ongoing Zika virus transmission should report cases to public health officials says the CDC.