1
COVID-19 Update: mNEXSPIKE — A New Moderna mRNA Vaccine for COVID-19
The Medical Letter on Drugs and Therapeutics • July 21, 2025; (Issue 1733)
The FDA has licensed mNEXSPIKE (Moderna), an
mRNA vaccine, for prevention of COVID-19 in adults
≥65 years old and in persons 12-64 years old who
have a condition that puts them at high risk for
severe outcomes from COVID-19. Spikevax, the
original Moderna mRNA COVID-19 vaccine, remains
in production2; it is licensed for use in persons
≥12 years old and is available under an Emergency
Use Authorization (EUA) for children 6 months to
11 years old.
2
Suzetrigine (Journavx) — A Sodium Channel Blocker for Acute Pain
The Medical Letter on Drugs and Therapeutics • March 3, 2025; (Issue 1723)
The FDA has approved suzetrigine (Journavx –
Vertex), a selective sodium channel blocker, for oral
treatment of moderate to severe acute pain in adults.
Suzetrigine is the first sodium channel blocker to be
approved in the US for this indication and the first oral
nonopioid drug to be approved for treatment of pain
in over 25 years.
3
In Brief: OTC Ivermectin for Head Lice
The Medical Letter on Drugs and Therapeutics • June 26, 2023; (Issue 1679)
Topical ivermectin lotion 0.5% (Sklice, and generics),
which has been available by prescription since 2012,
is now FDA-approved for sale over the counter (OTC)
for treatment of head lice in patients ≥6 months old.
Ivermectin is also available by prescription as a 1%
cream (Soolantra) approved for topical treatment of
inflammatory lesions of rosacea and in oral tablets
(Stromectol, and generics) for treatment of various
parasitic infections.
4
Capvaxive – A 21-Valent Pneumococcal Conjugate Vaccine
The Medical Letter on Drugs and Therapeutics • October 14, 2024; (Issue 1713)
The FDA has licensed Capvaxive (PCV21; Merck),
a 21-valent pneumococcal conjugate vaccine, for
prevention of invasive pneumococcal disease (IPD)
and pneumococcal pneumonia in adults. Four other
pneumococcal vaccines are currently available in the
US: Prevnar 20 (PCV20), Vaxneuvance (PCV15), and
Prevnar 13 (PCV13) are conjugate vaccines licensed
for use in persons ≥6 weeks old, and Pneumovax 23
(PPSV23) is a pneumococcal polysaccharide vaccine
licensed for use in persons ≥2 years old (see Table 1).
5
Insect Repellents
The Medical Letter on Drugs and Therapeutics • July 7, 2025; (Issue 1732)
The Centers for Disease Control and Prevention
(CDC) and the Environmental Protection Agency (EPA)
recommend using insect repellents to avoid being
bitten by mosquitoes, ticks, and other arthropods
that transmit disease-causing pathogens. Repellents
applied to exposed skin should be used in conjunction
with other preventive measures such as wearing long-sleeved
shirts, pants, and socks and avoiding outdoor
activities during peak mosquito-biting times. Some
insect repellents are listed in Table 1.
6
COVID-19 Update: Full Approval for Novavax COVID-19 Vaccine
The Medical Letter on Drugs and Therapeutics • July 21, 2025; (Issue 1733)
Nuvaxovid, the adjuvanted protein subunit COVID-19
vaccine marketed by Novavax, has received full
approval from the FDA to prevent COVID-19 caused
by severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) in all adults ≥65 years old and in adults
12-64 years old who have at least one underlying
condition that puts them at high risk for severe
outcomes from COVID-19. The vaccine was previously
available under an FDA Emergency Use Authorization
(EUA) for use in persons ≥12 years old.1 Nuvaxovid is
the first protein-based COVID-19 vaccine to receive
full approval from the FDA; the mRNA COVID-19
vaccines Comirnaty and Spikevax are approved for use
in patients ≥12 years old.
7
COVID-19 Update: mRNA COVID-19 Vaccines and Myocarditis
The Medical Letter on Drugs and Therapeutics • July 21, 2025; (Issue 1733)
The FDA has required the manufacturers of the mRNA
COVID-19 vaccines Comirnaty (Pfizer-BioNTech)
and Spikevax (Moderna) to revise their labels to
include updated information about the risks of
myocarditis/pericarditis. The FDA requested that
the manufacturers submit the proposed labeling
changes or contest the agency's requirement for the
safety update by May 17, 2025. As of June 4th, to our
knowledge, the labels of Comirnaty and Spikevax
have not been updated and neither manufacturer has
submitted a rebuttal.
8
Treatment of Common Respiratory Tract Infections
The Medical Letter on Drugs and Therapeutics • April 17, 2023; (Issue 1674)
Most respiratory tract infections are caused by
viruses. Bacterial respiratory tract infections are
usually treated empirically with antibiotic therapy
that targets the most probable causative pathogens.
Recommended antibiotic regimens for outpatient
treatment of some common respiratory tract
infections are listed in Table 1 for adults and Table 2
for children.
9
Antiviral Drugs for Seasonal Influenza for 2024-2025
The Medical Letter on Drugs and Therapeutics • December 9, 2024; (Issue 1717)
Influenza is generally a self-limited illness, but
pneumonia, respiratory failure, and death can occur,
especially in persons at increased risk for influenza
complications (see Table 1). Updated information on
influenza activity and antiviral resistance is available
from the CDC at cdc.gov/flu.
10
In Brief: Low-Dose Chlorthalidone (HemiClor) for Hypertension
The Medical Letter on Drugs and Therapeutics • July 21, 2025; (Issue 1733)
The FDA has approved a 12.5-mg tablet formulation
of the thiazide-like diuretic chlorthalidone (HemiClor –
Ingenus) for treatment of hypertension. Chlorthalidone
has been available for years in 15-, 25-, and 50-mg
tablets (Thalitone, and generics) and in fixed-dose
combinations with azilsartan medoxomil (Edarbyclor)
and atenolol (Tenoretic, and generics).