Cases in several Americas subregions are sharply above last year's totals and 5-year averages.
Cross-reactivity among orthoflaviviruses should be considered when testing vaccines against the diseases they cause, the researchers say.
So far this year, 90 countries globally have reported active dengue transmission, with the Americas as the hardest-hit region.
Transmission is increasing in Central America, Mexico, and the Caribbean regions, with cases well above last year at this time.
The additions split the current genotypes of the mosquito-borne virus into "major" and "minor" lineages.
The WHO recommends its use in children ages 6 to 16 years old in settings where the dengue burden and transmission intensity is high.
The newborns had a 67% and 133% greater risk of being classified as very and extremely low birth weight, respectively.
Cases are even rising in countries such as Costa Rica and Mexico that typically see dengue rises in the second half of the year.
The territory last declared an emergency owing to dengue in 2012.
Dengue cases in the Americas so far this year are outpacing last year's record activity.
